Polymer and process for producing the same

ABSTRACT

The present invention relates to a polymer having a melt tension (MT (g)) substantially the same as or lower than that of a conventional polymer which is substantially the same as the polymer in the recurring unit of the main skeleton, the molecular weight, the molecular weight distribution and the crystallinity, and having a flow activation energy (Ea (KJ/mol)) larger than a value obtained by adding 5 KJ/mol to the Ea value of the conventional polymer. A preferred example of the polymer is a branched polyolefin comprising 50 to 100% by mol of recurring units derived from ethylene and 0 to 50% by mol of recurring units derived from an α-olefin of 3 to 20 carbon atoms and having the following properties: the flow activation energy (Ea (KJ/mol)) and the α-olefin content (C (% by weight)) satisfy a specific relation, and the melt tension (MT (g)) and the melt flow rate (MFR (g/10 min)) satisfy a specific relation. This branched polyolefin is excellent in moldability and mechanical strength.

TECHNICAL FIELD

[0001] The present invention relates to novel polymers having equivalentor smaller melt tension (MT (g)) and larger flow activation energy valuethan conventional polymers having equivalent recurring unit of the mainskeleton and substantially the same molecular weight, molecular weightdistribution and crystallinity as those of the novel polymers. Moreparticularly, the invention relates to a branched polyolefin of novelstructure among the above polymers, said branched polyolefin mainlycontaining ethylene units and having as a side chain an olefin chainhaving few methyl branches, and a process for preparing the same.

BACKGROUND ART

[0002] Low-density polyethylene (LDPE) produced by a high-pressureradical method is well known as a branched polyolefin, and the sidechain of the LDPE has a non-linear tree-like structure. Such a structureis excellent in moldability and advantageous in melt processing, but onthe other hand, it has a disadvantage of lowering mechanical strength ofthe polymer.

[0003] In the use application where mechanical strength is necessary,therefore, linear low-density polyethylene (LLDPE) obtained bycopolymerization of ethylene and a higher α-olefin is generallyemployed. However, the length of the side chain of the LLDPE isextremely shorter than that of the LDPE, so that the LLDPE does not havegood moldability that is an advantage of the LDPE.

[0004] On this account, development of branched polyethylene which issuperior to the LDPE in mechanical strength and melt processability hasbeen made enthusiastically. For example, a macromonomer produced by theuse of a metallocene catalyst is copolymerized with ethylene to obtain abranched polymer satisfying the above-mentioned properties, as describedin National Publication of International Patent No. 502303/1996. Thepolymer obtained by the process described in this publication has astructure similar to that of LLDPE, and its side chain does not becomecompletely linear and has a methyl branch. Although the polymer of thisstructure is superior to LDPE in mechanical strength, the methyl branchlowers mechanical strength, and therefore the mechanical strength of thepolymer is sometimes unsatisfactory depending upon the purpose.

[0005] In Japanese Patent Laid-Open Publications No. 316711/1998 and No.38418/2000, a process for preparing a branched polymer by copolymerizinga macromonomer and an α-olefin is disclosed, but a method of inhibitingformation of methyl branch of the side chain has not been known yet. Forthe invention described in the above publications, it is difficult tocontrol the weight-average molecular weight of the side chain to be inthe range of 1,000 to 10,000, and there is a limitation on the processfor preparing a branched polymer having a main chain and a side chaindifferent in the composition.

[0006] In National Publication of International Patent No. 502303/1996,there is disclosed a branched polyolefin comprising: a main chain (b) ofa homopolymer or a copolymer of C2-C30 alpha olefins; and side chains(a) of at least 250 carbon atoms comprising a homopolymer or a copolymerof C2-C30 alpha olefins, said side chains being distributed along thepolymer main chain at an average frequency of 0.1 to 5 side chains per1000 main chain carbon atoms, said branched polymer having a weightaverage molecular weight of at least 30,000 and an MW/Mn of 6 or less.

[0007] In view of such prior art as described above, the presentinventors have found novel polymers having equivalent or smaller melttension (MT (g)) and larger flow activation energy value thanconventional polymers having equivalent recurring unit of the mainskeleton and substantially the same molecular weight, molecular weightdistribution and crystallinity as those of the novel polymers. Thepresent inventors have further found a branched polyolefin of novelstructure among the above polymers, said polyolefin mainly containingmainly ethylene units and having as a side chain an olefin chain havingfew methyl branches, and a process for preparing the branchedpolyolefin. The present inventors have studied, as the branchedpolyolefin, a branched polyolefin containing scarcely any methyl branchand having a specific weight-average molecular weight, and as a result,they have found that the desired branched polyolefin can be obtained bythe use of a catalyst containing specific two different transition metalcompounds. Based on the finding, the present invention has beenaccomplished.

[0008] That is to say, it is an object of the present invention toprovide a novel polymer having characteristic melt tension and flowactivation energy which are not observed in the conventional polymers,and in particular, it is an object of the invention to provide abranched polyolefin having excellent moldability and mechanical strengthand a process for preparing the same.

DISCLOSURE OF THE INVENTION

[0009] The novel polymer according to the invention is a polymer havinga melt tension (MT (g)) that is substantially the same as or lower thanthat of a conventional polymer which is substantially the same as thisnovel polymer in the recurring unit of the main skeleton, the molecularweight, the molecular weight distribution and the crystallinity, andhaving a flow activation energy (Ea (KJ/mol)) that is larger than avalue obtained by adding 5 KJ/mol to the Ea value of the conventionalpolymer.

[0010] In an embodiment of this polymer, it is desirable that therecurring unit of the main skeleton is constituted of carbon andhydrogen, and optionally oxygen, and the polymer is substantiallythermoplastic Another embodiment of this polymer is a polymer which hasbranches and in which the main skeleton is constituted of olefins of 2to 8 carbon atoms.

[0011] The first embodiment of the branched polyolefin according to theinvention is a branched polyolefin comprising 50 to 100% by mol ofrecurring units derived from ethylene and 0 to 50% by mol of recurringunits derived from an α-olefin of 3 to 7 carbon atoms and having thefollowing properties:

[0012] the flow activation energy (Ea (KJ/mol)) and the α-olefin content(C (% by weight)) satisfy the following relation:

[0013] in the case where the number of carbon atoms of the α-olefin is 3and C≧10% by weight:

[0014] Ea≧0.130×C+28.7,

[0015] in the case where the number of carbon atoms of the α-olefin is 4to 7 and C≧4.1% by weight:

[0016] Ea≧0.385×C+28.7,

[0017] in the case where the number of carbon atoms of the α-olefin is 3and C<10% by weight (including the case where the α-olefin content is0), and in the case where the number of carbon atoms of the α-olefin is4 to 7 and C<4.1% by weight:

[0018] Ea≧30,

[0019] and

[0020] the melt tension (MT (g)) and the melt flow rate (MFR (g/10 min))satisfy the following relation:

[0021] MT≦2.2×MFR^(−0.88).

[0022] This branched polyolefin comprises, for example,

[0023] (i) recurring units derived from at least one olefin selectedfrom ethylene and olefins of 3 to 7 carbon atoms, and

[0024] (ii) recurring units derived from a vinyl-terminated macromonomercomprising 50 to 100% by mol of recurring units derived from ethyleneand 50 to 0% by mol of recurring units derived from an olefin of 4 to 7carbon atoms, having a weight-average molecular weight of 600 to 3,500and having less than 0.1 methyl branch, as measured by ¹³C-NMR, based on1,000 carbon atoms.

[0025] The second embodiment of the branched polyolefin according to theinvention is a branched polyolefin comprising 50 to 100% by mol ofrecurring units derived from ethylene and 0 to 50% by mol of recurringunits derived from an α-olefin of 8 to 20 carbon atoms and having thefollowing properties:

[0026] the flow activation energy (Ea (KJ/mol)) and the α-olefin content(C (% by weight)) satisfy the following relation:

[0027] in the case of C≧4.1% by weight:

[0028] Ea≧0.385×C+28.7,

[0029] in the case of C<4.1% by weight:

[0030] Ea≧30,

[0031] and

[0032] the melt tension (MT (g)) and the melt flow rate (MFR (g/10 min))satisfy the following relation:

[0033] MT≦2.2×MFR^(−0.88).

[0034] This branched polyolefin comprises, for example,

[0035] (i) recurring units derived from at least one olefin selectedfrom ethylene and olefins of 8 to 20 carbon atoms, and

[0036] (ii) recurring units derived from a vinyl-terminated macromonomercomprising 50 to 100% by mol of recurring units derived from ethyleneand 50 to 0% by mol of recurring units derived from an olefin of 3 to 20carbon atoms, having a weight-average molecular weight of 600 to 3,500and having less than 0.1 methyl branch, as measured by ¹³C-NMR, based on1,000 carbon atoms.

[0037] The third embodiment of the branched polyolefin according to theinvention is a branched polyolefin comprising:

[0038] (i) recurring units derived from at least one olefin selectedfrom olefins of 2 to 20 carbon atoms, and

[0039] (ii) recurring units derived from a vinyl-terminated macromonomercomprising 50 to 100% by mol of recurring units derived from ethyleneand 50 to 0% by mol of recurring units derived from an olefin of 4 to 20carbon atoms, having a weight-average molecular weight of 600 to 200,000and having less than 0.1 methyl branch, as measured by ¹³C-NMR, based on1,000 carbon atoms.

[0040] This embodiment includes a preferred embodiment wherein theweight-average molecular weight of the vinyl-terminated macromonomer isin the range of 1,000 to 10,000, and further includes another preferredembodiment wherein the weight-average molecular weight of thevinyl-terminated macromonomer is in the range of 600 to 3,500.

[0041] The process for preparing a branched polyolefin according to theinvention is a process comprising polymerizing at least one olefinselected from olefins of 2 to 20 carbon atoms using an olefinpolymerization catalyst comprising:

[0042] (A) a transition metal compound containing a ligand havingcyclopentadienyl skeleton,

[0043] (B) a transition metal compound represented by the followingformula (I), and

[0044] (C) at least one compound selected from:

[0045] (C-1) an organometallic compound,

[0046] (C-2) an organoaluminum oxy-compound, and

[0047] (C-3) a compound which reacts with the transition metal compound(A) or the transition metal compound (B) to form an ion pair,

[0048] to prepare any one of the above-described branched polyolefins;

[0049] wherein M is a transition metal atom of Group 4 to Group 5 of theperiodic table, m is an integer of 1 to 2, R¹ is an aliphatichydrocarbon group or an alicyclic hydrocarbon group, R² to R⁵ may be thesame or different and are each a hydrogen atom, a hydrocarbon group, ahydrocarbon-substituted silyl group, an oxygen-containing group, anitrogen-containing group or a sulfur-containing group, R⁶ is ahydrocarbon group or a hydrocarbon-substituted silyl group, n is anumber satisfying a valence of M, X is a hydrogen atom, a halogen atom,a hydrocarbon group, an oxygen-containing group, a sulfur-containinggroup, a nitrogen-containing group, a boron-containing group, analuminum-containing group, a phosphorus-containing group, ahalogen-containing group, a heterocyclic compound residue, asilicon-containing group, a germanium-containing group or atin-containing group, and when n is 2 or greater, plural groupsindicated by X may be the same or different, and plural groups indicatedby X may be bonded to form a ring.

[0050] In the process for preparing a branched polyolefin according tothe invention, it is also preferable that the polymerization is carriedout continuously under at least two different polymerization conditions,and the polymerization includes

[0051] polymerization conducted under such conditions that the yield ofa polymer produced by the transition metal compound (B) becomes higherthan the yield of a polymer produced by the transition metal compound(A) and

[0052] polymerization conducted under such conditions that the yield ofa polymer produced by the transition metal compound (A) becomes higherthan the yield of a polymer produced by the transition metal compound(B).

BRIEF DESCRIPTION OF THE DRAWINGS

[0053]FIG. 1 is an explanatory view showing steps for preparing anolefin polymerization catalyst for use in the present invention.

[0054]FIG. 2 is a GPC chart of a polymer obtained in Example 1.

BEST MODE FOR CARRYING OUT THE INVENTION

[0055] The polymers according to the invention, such as a branchedpolyolefin, and a process for preparing the same are described in detailhereinafter The meaning of the term “polymerization” used herein is notlimited to “homopolymerization” but may comprehend “copolymerization”.Also, the meaning of the term “polymer” used herein is not limited to“homopolymer” but may comprehend “copolymer”.

[0056] The novel polymer according to the invention is a polymer havinga melt tension (MT (g)) that is substantially the same as or lower thanthat of a conventional polymer which is substantially the same as thisnovel polymer in the recurring unit of the main skeleton, the molecularweight, the molecular weight distribution and the crystallinity, andhaving a flow activation energy (Ea (KJ/mol)) that is larger than avalue obtained by adding 5 KJ/mol to the Ea value of the conventionalpolymer.

[0057] The expression “substantially the same” used herein means that,as compared with the polymer of the invention, the type of the recurringunit is identical, a difference in the molecular weight (weight-averagemolecular weight) is in the range of ±30%, a difference in the molecularweight distribution (Mw/Mn) is in the range of ±30%, and a difference inthe crystallinity is in the range of ±10%.

[0058] The crystallinity can be measured by X-ray diffractometry (S. L.AGGARWAL; J. Polymer Sci. 18, 17 (1955)) or the like.

[0059] The recurring unit of the main chain of the polymer is notspecifically limited, and various recurring units can be exemplified. Ofthese, preferable is a recurring unit constituted of carbon andhydrogen, or carbon, hydrogen and oxygen, and the polymer is desired tobe substantially thermoplastic.

[0060] Examples of the recurring units include olefins, such as anα-olefin, a cycloolefin, a diolefin and an aromatic group-containingvinyl compound. Of these, olefins of 2 to 8 carbon atoms are desirable.

[0061] The first embodiment of the branched polyolefin according to theinvention comprises recurring units derived from ethylene and recurringunits derived from an α-olefin of 3 to 20 carbon atoms.

[0062] Examples of the α-olefins of 3 to 20 carbon atoms includestraight-chain or branched α-olefins of 3 to 20 carbon atoms, such aspropylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene,4-methyl-1-pentene, 3-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene,1-tetradecene, 1-hexadecene, 1-octadecene and 1-eicosene; andcycloolefins of 4 to 20 carbon atoms, such as cyclopentene,cycloheptene, norbornene, 5-methyl-2-norbornene, tetracyclododecene and2-methyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronap hthalene. Inthe branched polyolefin, two or more kinds of the recurring unitsderived from the α-olefins of 3 to 20 carbon atoms may be contained.

[0063] When the branched polyolefin of the invention comprises 50 to100% by mol of recurring units derived from ethylene and 0 to 50% by molof recurring units derived from an α-olefin of 3 to 7 carbon atoms, thisbranched polyolefin has the following properties:

[0064] the flow activation energy (Ea (KJ/mol)) and the α-olefin content(C (% by weight)) satisfy the following relation:

[0065] in the case where the number of carbon atoms of the α-olefin is 3and C≧10% by weight:

[0066] Ea≧0.130×C+28.7,

[0067] preferably Ea≧0.144×C+28.7,

[0068] more preferably Ea≧0.178×C+28.7,

[0069] in the case where the number of carbon atoms of the α-olefin is 4to 7 and C≧4.1% by weight:

[0070] Ea≧0.385×C+28.7,

[0071] preferably Ea≧0.425×C+28.7,

[0072] more preferably Ea≧0.528×C+28.7,

[0073] in the case where the number of carbon atoms of the α-olefin is 3and C<10% by weight (including the case where the α-olefin content is0), and in the case where the number of carbon atoms of the α-olefin is4 to 7 and C<4.1% by weight:

[0074] Ea≧30,

[0075] preferably Ea≧35,

[0076] more preferably Ea≧40,

[0077] and

[0078] the melt tension (MT (g)) and the melt flow rate (MFR (g/10 min))satisfy the following relation:

[0079] MT≦2.2×MFR^(−0.88),

[0080] preferably MT≦2.0×MFR^(−0.88).

[0081] The first embodiment of the branched polyolefin comprises, forexample,

[0082] (i) recurring units derived from at least one olefin selectedfrom ethylene and olefins of 3 to 7 carbon atoms, and

[0083] (ii) recurring units derived from a vinyl-terminated macromonomercomprising 50 to 100% by mol of recurring units derived from ethyleneand 50 to 0% by mol of recurring units derived from an olefin of 4 to 7carbon atoms, having a weight-average molecular weight of 600 to 3,500and having less than 0.1 methyl branch, as measured by ¹³C-NMR, based on1,000 carbon atoms.

[0084] This vinyl-terminated macromonomer has a weight-average molecularweight (Mw), as measured by gel permeation chromatography (GPC), ofusually of 600 to 3,500, preferably 700 to 3,500, more preferably 800 to3,500, and Mw/Mn (Mn: number-average molecular weight) of usually notless than 1.5 and less than 4.0, preferably not less than 1.8 and lessthan 3.8.

[0085] In the vinyl-terminated macromonomer, the number of methylbranches, as measured by ¹³C-NMR, is usually less than 0.1, preferablyless than 0.08, more preferably less than 0.05, based on 1,000 carbonatoms.

[0086] The vinyl-terminated macromer can be prepared by copolymerizingethylene and an olefin of 4 to 7 carbon atoms or polymerizing ethylenealone, using a catalyst containing, for example, the later-describedtransition metal compound (B).

[0087] This branched polyolefin has a weight-average molecular weight ofusually 30,000 to 500,000, preferably 50,000 to 200,000, and MFR ofusually 0.01 to 100 g/10 min, preferably 0.05 to 10 g/10 min.

[0088] The second embodiment of the branched polyolefin according to theinvention, which comprises 50 to 100% by mol of recurring units derivedfrom ethylene and 0 to 50% by mol of recurring units derived from anα-olefin of 8 to 20 carbon atoms, has the following properties:

[0089] the flow activation energy (Ea (KJ/mol)) and the α-olefin content(C (% by weight)) satisfy the following relation:

[0090] in the case of C≧4.1% by weight:

[0091] Ea≧0.385×C+28.7,

[0092] preferably Ea≧0.425×C+28.7,

[0093] more preferably Ea≧0.528×C+28.7,

[0094] in the case of C<4.1% by weight:

[0095] Ea≧30,

[0096] preferably Ea≧35,

[0097] more preferably Ea≧40,

[0098] and

[0099] the melt tension (MT (g)) and the melt flow rate (MFR (g/10 min))satisfy the following relation:

[0100] MT≦2.2×MFR^(−0.88),

[0101] preferably MT≦2.0×MFR^(−0.88).

[0102] The second embodiment of the branched polyolefin comprises, forexample,

[0103] (i) recurring units derived from at least one olefin selectedfrom ethylene and olefins of 8 to 20 carbon atoms, and

[0104] (ii) recurring units derived from a vinyl-terminated macromonomercomprising 50 to 100% by mol of recurring units derived from ethyleneand 50 to 0% by mol of recurring units derived from an olefin of 3 to 20carbon atoms, having a weight-average molecular weight of 600 to 3,500and having less than 0.1 methyl branch, as measured by ¹³C-NMR, based on1,000 carbon atoms.

[0105] This vinyl-terminated macromonomer has a weight-average molecularweight (Mw), as measured by gel permeation chromatography (GPC), ofusually of 600 to 3,500, preferably 700 to 3,500, more preferably 800 to3,500, and Mw/Mn (Mn: number-average molecular weight) of usually notless than 1.5 and less than 4.0, preferably not less than 1.8 and lessthan 3.8.

[0106] In the vinyl-terminated macromonomer, the number of methylbranches, as measured by ¹³C-NMR, is usually less than 0.1, preferablyless than 0.08, more preferably less than 0.05, based on 1,000 carbonatoms.

[0107] The vinyl-terminated macromer can be prepared by copolymerizingethylene and an olefin of 8 to 20 carbon atoms or polymerizing ethylenealone, using a catalyst containing, for example, the later-describedtransition metal compound (B).

[0108] This branched polyolefin has a weight-average molecular weight ofusually 30,000 to 500,000, preferably 50,000 to 200,000, and MFR ofusually 0.01 to 100 g/10 min, preferably 0.05 to 10 g/10 min.

[0109] Large Ea means that the temperature dependence of the viscosityof the branched polyolefin is great, and when a branched polyolefinhaving large Ea is molded by extrusion, extrusion molding can be easilyperformed because the viscosity of the polyolefin in the vicinity of thedie is low, and when the molded product is then cooled, the viscosityrapidly rises. Hence, the molded product comes to be hardly stretched,and as a result, the product hardly suffers stretching nonuniformity.

[0110] The branched polyolefin according to the invention has low MT andthereby has good drawdown (high-speed take-off properties). Hence, ifthe polyolefin is taken off in a molten state at a high speed, breakinghardly occurs.

[0111] The third embodiment of the branched polyolefin according to theinvention comprises:

[0112] (i) recurring units derived from at least one olefin selectedfrom olefins of 2 to 20 carbon atoms, and

[0113] (ii) recurring units derived from a vinyl-terminated macromonomerhaving a weight-average molecular weight of 600 to 200,000, preferably1,000 to 100,000, and having less than 0.1 methyl branch, as measured by¹³C-NMR, based on 1,000 carbon atoms.

[0114] The third embodiment of the branched polyolefin comprising therecurring units (i) and the recurring units (ii) is obtained bycopolymerizing at least one olefin selected from olefins of 2 to 20carbon atoms and the vinyl-terminated macromonomer.

[0115] Examples of the olefins of 2 to 20 carbon atoms include ethyleneand the aforesaid olefins of 3 to 20 carbon atoms. Of these, an olefinselected from ethylene, propylene, 1-butene, 1-hexene, 1-octene andnorbornene is preferable. These olefins of 2 to 20 carbon atoms can beused singly or in combination of two or more kinds.

[0116] The vinyl-terminated macromonomer is a (co)polymer mainlycontaining recurring units derived from ethylene, and in thevinyl-terminated macromonomer, recurring units derived from ethylene aredesirably present in amounts of usually 50 to 100% by mol, preferably 55to 100% by mol, more preferably 65 to 100% by mol, most preferably 70 to100% by mol, and recurring units derived from an olefin of 4 to 20carbon atoms are desirably present in amounts of 0 to 50% by mol,preferably 0 to 45% by mol, more preferably 0 to 35% by mol,particularly preferably 0 to 30% by mol.

[0117] Examples of the olefins of 4 to 20 carbon atoms include theaforesaid straight-chain or branched α-olefins and cycloolefins, exceptethylene and propylene. Of these, an olefin selected from 1-butene,1-hexene, 1-octene and norbornene is preferable.

[0118] The vinyl-terminated macromonomer has a weight-average molecularweight (Mw), as measured by gel permeation chromatography (GPC), ofusually of 1,000 to 10,000, preferably 1,500 to 9,000, more preferably2,000 to 8,000, still more preferably 2,500 to 7,000.

[0119] In the vinyl-terminated macromonomer, the number of methylbranches, as measured by ¹³C-NMR, is usually less than 0.1, preferablyless than 0.08, more preferably less than 0.05, based on 1,000 carbonatoms.

[0120] The vinyl-terminated macromonomer has Mw/Mn (Mn: number-averagemolecular weight) of usually not less than 1.5 and less than 4.0,preferably not less than 1.8 and less than 3.8.

[0121] The vinyl-terminated macromonomer can be prepared bycopolymerizing ethylene and an olefin of 4 to 20 carbon atoms orpolymerizing ethylene alone, using a catalyst containing, for example,the later-described transition metal compound (B).

[0122] The branched polyolefin of the third embodiment is a polyolefinobtained by copolymerizing (i) at least one olefin selected from olefinsof 2 to 20 carbon atoms and (ii) the above-mentioned vinyl-terminatedmacromonomer. This branched polyolefin has a weight-average molecularweight of usually 30,000 to 10,000,000, preferably 50,000 to 5,000,000,and Mw/Mn of usually 1.5 to 20, preferably 1.8 to 10, more preferably 2to 4, and has usually 0.01 to 60 side chains, preferably 0.1 to 50 sidechains, more preferably 1 to 40 side chains, still more preferably 6 to30 side chains, based on 1,000 carbon atoms of main chain.

[0123] The branched polyolefin according to the invention is desired tobe a polyolefin wherein the main chain is a (co)polymer of at least oneolefin selected from olefins of 2 to 20 carbon atoms, preferably a(co)polymer essentially containing at least one olefin selected fromolefins of 3 to 20 carbon atoms, and the side chain is an ethylenehomopolymer.

[0124] Next, methods for measuring flow activation energy, α-olefincontent, melt tension and melt flow rate are described.

[0125] Flow Activation Energy (Ea)

[0126] Using a Rheometrix Rheometer RDS-II, variance of an angularvelocity (ω (rad/sec)) of a storage elastic modulus (G′ (dyne/cm²)) wasmeasured. As a sample holder, parallel plates of 25 mm diameter wereused, and the sample thickness was about 2 mm. The measuringtemperatures were 140, 170, 200 and 230° C., and at each temperature, G′was measured in the range of 0.04≦ω≦400. The measuring points were 5points based on one figure of ω. The strain was appropriately selectedfrom the range of 2 to 25% so that the torque can be detected in themeasuring range and no torque-over occurs. After the measurement, flowcurves obtained under four temperature conditions were overlapped(reference temperature: 140° C.), and Ea was determined from theArrhenius type plot of the shift factor. Calculation was performed byplotting with a Microsoft tabular calculation software excel™. First,the data measured at the four measuring temperatures were plotted asboth logarithmic values, with ω as abscissa and G′ as ordinate. Flowcurves other than the flow curve of the measuring temperature of 140° C.were shifted along the ordinate so that they overlap the flow curve ofthe measuring temperature of 140° C., and the shift quantity is taken aslog(aT). To the reciprocal number of the measuring temperature (truemeasuring temperature being described as absolute temperature), log (aT)was plotted, and an inclination was determined by the method of leastsquares (linear approximation). When the correlation coefficient R2 was0.995 or less, shifting of the flow curves was done over again. Theinclination is taken as A.

Ea (KJ/mol)=2.303×8.314×A×(−1)/1000

[0127] wherein 2.303 is ln10, and 8.314 is a gas constant.

[0128] If a long branch is present, overlapping in the region of low ωis sometimes bad. In this case, the flow curve was shifted so as tooverlap in the region of high ω of about ω≧10 rad/sec.

[0129] α-Olefin Content

[0130] The α-olefin content was determined by ¹³C-NMR.

[0131] Melt Tension (MT)

[0132] The melt tension was determined by measuring a stress given whena molten polymer was stretched at a constant rate. That is, granulationpellets of a copolymer were used as a measuring sample, and themeasurement was carried out using a MT measuring machine manufactured byToyo Seiki Seisakusho under the conditions of a resin temperature of190° C., a barrel diameter of 9.55 mm, an extrusion speed of 15 mm/min,a take-up rate of 10 to 20 m/min, a nozzle diameter of 2.095 mm and anozzle length of 8 mm.

[0133] When the MT value was less than about 4, the full-scale range wasset to 5 g, and in this case, the MT value was expressed by a value downto the second decimal place. When the MT value was in the range of about4 to 9, the full-scale range was set to 10 g, and in this case, the MTvalue was expressed by a value down to the first decimal place. When theMT value was in the range of about 9 to 18, the full-scale range was setto 20 g, and in this case, the MT value was expressed by a value down tothe first decimal place.

[0134] Melt Flow Rate (MFR)

[0135] The melt flow rate was measured in accordance with ASTM D-1238under the conditions of a temperature of 190° C. and a load of 2.16 kg.

[0136] Number-Average Molecular Weight (Mn), Weight-Average MolecularWeight (Mw), Mw/Mn

[0137] The molecular weight was measured in the following manner usingWaters GPC-150C. Separatory columns of TSKgel GMH6-HT and TSKgelGMH6-HTL each having an inner diameter of 7.5 mm and a length of 600 mmwere used, and the column temperature was 140° C. Usingo-dichlorobenzene (available from Wako Junyaku Kogyo) as a mobile phaseand 0.025% by weight of BHT (available from Takeda Chemical Industries,Ltd.) as an antioxidant, a sample (concentration: 0.1% by weight, pour:500 microliter) was moved at a rate of 1.0 ml/min. As a detector, adifferential refractometer was used. As standard polystyrene,polystyrene of Mw<1000 and Mw>4×10⁶ available from Tohso Co. andpolystyrene of 1000≦Mw≦4×10⁶ available from Pressure Chemical Co. wereused. In the calculation of molecular weight, universal calibration wasmade, and the obtained value is a value in terms of PE.

[0138] The peak separation was carried out by the following manner usinga Toso analytical apparatus SC8010. A minimum point between peaks wasdetermined from the chart. From the point, a perpendicular was drawntoward the base line, and Mw, Mn, Mw/Mn and peak intensity ratio at eachpeak were calculated.

[0139] Measurements of the Number of Methyl Branches and the Number ofHexyl Branches

[0140] The number of methyl branches based on 1,000 carbon atoms in thepolymer molecular chain was measured by ¹³C-NMR. In the measurement, aJapan Electron Optics Laboratory Lambda 500 type nuclear magneticresonance apparatus (¹H: 500 MHz) was used. The number of integrationtimes was 10,000 to 30,000. As the chemical shift base, a peak (29.97ppm) of the main chain methylene was used. The measurement was made byplacing 250 to 400 mg of a sample and 3 ml of a mixed liquid ofo-dichlorobenzene of special grade available from Wako Junyaku Kogyo K.K. and benzene-d6 available from ISOTEC Co. (5:1, by volume) in acommercially available NMR measuring quarts glass tube of 10 mm diameterand heating them at 120° C. to give a homogeneous dispersion. Assignmentof each absorption in the NMR spectrum was carried out in accordancewith Region of Chemistry, extra issue No. 141, NMR-Outline AndExperimental Guide (I), pp. 132-133. The number of methyl branches basedon 1,000 carbon atoms is calculated from a ratio of the integralintensity of absorption (19.99 ppm) of a methyl group derived frommethyl branch to the integral total sum of absorptions appearing in theregion of 5 to 45 ppm. The number of hexyl (or longer) branches based on1,000 carbon atoms is calculated from a ratio of the integral intensityof methylene (C6+3) appearing at 32.2 ppm to the integral total sumthereof.

Preparation

[0141] The branched polyolefin according to the invention can beprepared by the use of, for example, an olefin polymerization catalystcomprising:

[0142] (A) a transition metal compound containing a ligand havingcyclopentadienyl skeleton,

[0143] (B) a transition metal compound represented by the followingformula (I):

[0144] and

[0145] (C) at least one compound selected from:

[0146] (C-1) an organometallic compound,

[0147] (C-2) an organoaluminum oxy-compound, and

[0148] (C-3) a compound which reacts with the transition metal compound(A) or the transition metal compound (B) to form an ion pair.

[0149] The components for forming the olefin polymerization catalystemployable for the preparation of the branched polyolefin are describedbelow.

(A) Transition Metal Compound Containing Ligand Having CyclopentadienylSkeleton

[0150] Although the transition metal compound (A) containing a ligandhaving cyclopentadienyl skeleton, which is used for forming the olefinpolymerization catalyst, is not specifically restricted, a metallocenecompound per se publicly known is available. Examples of such compoundsinclude metallocene compounds of transition metals such as titanium,vanadium, chromium, zirconium and hafnium, and any of compounds whichare liquid or solid under the use conditions is employable. Thetransition metal compound may be a single compound, may be supported onanother compound, may be a homogeneous mixture with another compound, ormay be a complex or double compound with another compound.

[0151] Of the metallocene compounds per se publicly known, a metallocenecompound of chiral structure having C2 symmetry or C1 symmetry ispreferably used in the present invention.

[0152] Preferred examples of the metallocene compounds of chiralstructure having C2 symmetry include

[0153] rac-ethylene-bis(indenyl)zirconium dichloride,

[0154] rac-ethylene-bis(tetrahydroindenyl)zirconium dichloride,

[0155] rac-dimethylsilylene-bis(2,3,5-trimethylcyclopentadienyl)zirconium dichloride,

[0156] rac-dimethylsilylene-bis[1-(4-phenylindenyl)]zirconiumdichloride,

[0157] rac-dimethylsilylene-bis[1-(2-methyl-4-phenylindenyl)]zirconiumdichloride,

[0158]rac-dimethylsilylene-bis{1-[2-methyl-4-(1-naphthyl)indenyl]}zirconiumdichloride,

[0159]rac-dimethylsilyiene-bis{1-[2-methyl-4-(2-naphthyl)indenyl]}zirconiumdichloride,

[0160] rac-dimethylsilylene-bis{1-[2-methyl-4-(1-anthryl)indenyl]}zirconium dichloride,

[0161]rac-dimethylsilylene-bis{1-[2-methyl-4-(9-anthryl)indenyl]}zirconiumdichloride,

[0162]rac-dimethylsilyiene-bis{1-[2-methyl-4-(9-phenanthryl)indenyl]}zirconiumdichloride,

[0163]rac-dimethylsilylene-bis{1-[2-methyl-4-(o-chlorophenyl)indenyl]}zirconiumdichloride,

[0164] rac-dimethylsilylene-bis{1-[2-methyl-4-(pentafluorophenyl)indenyl]}zirconium dichloride,

[0165] rac-dimethylsilylene-bis[1-(2-ethyl-4-phenylindenyl)]zirconiumdichloride,

[0166]rac-dimethylsilylene-bis{1-[2-ethyl-4-(1-naphthyl)indenyl]}zirconiumdichloride,

[0167]rac-dimethylsilylene-bis{1-[2-ethyl-4-(9-phenanthryl)indenyl]}zirconiumdichloride,

[0168] rac-dimethylsilylene-bis[1-(2-n-propyl-4-phenylindenyl)]zirconiumdichloride,

[0169]rac-dimethylsilylene-bis{1-[2-n-propyl-4-(1-naphthyl)indenyl]}zirconiumdichloride and

[0170] rac-dimethylsilylene-bis{1-[2n-propyl-4-(9-phenanthryl)indenyl]}zirconium dichloride.

[0171] Preferred examples of the metallocene compounds of chiralstructure having C1 symmetry include

[0172]ethylene[2-methyl-4-(9-phenanthryl)-1-indenyl](9-fluorenyl)zirconiumdichloride,

[0173]ethylene[2-methyl-4-(9-phenanthryl)-1-indenyl](2,7-dimethyl-9-fluorenyl)zirconiumdichloride,

[0174] dimethylsilylene(9-fluorenyl)(3-t-butylcyclopentadienyl)zirconiumdichloride and

[0175] diphenylsilylene(9-fluorenyl)(3-t-butylcyclopentadienyl)zirconiumdichloride.

[0176] Of the hitherto known metallocene compounds, metallocenecompounds having only one substituted cyclopentadienyl group are alsoemployable as the metallocene compounds preferably used in theinvention.

[0177] For example, there can be mentioned (tertiarybutylamido)(tetramethyl-η⁵-cyclopentadienyl)-1,2-ethane diylzirconiumdichloride,

[0178](tertiarybutylamido)(tetramethyl-η⁵-cyclopentadienyl)-1,2-ethanediyltitaniumdichloride,

[0179] (methylamido)(tetramethyl-η⁵-cyclopentadienyl)-1,2-ethanediylzirconium dichloride,

[0180] (methylamido)(tetramethyl-η⁵-cyclopentadienyl)-1,2-ethanediyltitanium dichloride,

[0181] (ethylamido)(tetramethyl-η⁵-cyclopentadienyl)-1,2-ethanediylzirconium dichloride,

[0182] (ethylamido)(tetramethyl-η⁵-cyclopentadienyl)-1,2-ethanediyltitanium dichloride,

[0183](tertiarybutylamido)dimethyl(tetramethyl-η⁵-cyclopentadienyl)silanetitaniumdichloride,

[0184](tertiarybutylamido)dimethyl(tetramethyl-η⁵-cyclopentadienyl)silanezirconiumdibenzyl,

[0185](benzylamido)dimethyl(tetramethyl-η⁵-cyclopentadienyl)silanetitaniumdichloride and

[0186] (phenylphosphido)dimethyl(tetramethyl-η⁵-cyclopentadienyl)silanezirconium dibenzyl.

[0187] Of the hitherto known metallocene compounds, metallocenecompounds having two substituted cyclopentadienyl groups which are notbridged are also employable as the metallocene compounds preferably usedin the invention.

[0188] For example, there can be mentioned

[0189] bis(methylcyclopentadienyl)zirconium dichloride,

[0190] bis(dimethylcyclopentadienyl)zirconium dichloride,

[0191] bis(dimethylcyclopentadienyl)zirconium ethoxychloride,

[0192] bis(dimethylcyclopentadienyl)zirconium

[0193] bis(trifluoro-methanesulfonato),

[0194] bis(ethylcyclopentadienyl)zirconium dichloride,

[0195] bis(propylcyclopentadienyl)zirconium dichloride,

[0196] bis(methylpropylcyclopentadienyl)zirconium dichloride,

[0197] bis(butylcyclopentadienyl)zirconium dichloride,

[0198] bis(methylbutylcyclopentadienyl)zirconium dichloride,

[0199] bis(methylbutylcyclopentadienyl)zirconium

[0200] bis(trifluoro-methanesulfonato),

[0201] bis(trimethylcyclopentadienyl)zirconium dichloride,

[0202] bis(tetramethylcyclopentadienyl)zirconium dichloride,

[0203] bis(pentamethylcyclopentadienyl)zirconium dichloride,

[0204] bis(hexylcyclopentadienyl)zirconium dichloride and

[0205] bis(trimethylsilylcyclopentadienyl)zirconium dichloride.

[0206] Of the above metallocene compounds, more preferable aremetallocene compounds having only one substituted cyclopentadienylgroup, and particularly preferable are metallocene compounds having onlyone substituted cyclopentadienyl group and containing titanium as thecentral metal.

[0207] The transition metal compounds (A) mentioned above can be usedsingly or in combination or two or more kinds.

(B) Transition Metal Compound

[0208] The transition metal compound (B) for forming the olefinpolymerization catalyst is a compound represented by the followingformula (I):

[0209] wherein N-M generally indicates coordination, but in the presentinvention, they do not need to be coordinated.

[0210] In the formula (I), M is a transition metal atom of Group 4 orGroup 5 of the periodic table, such as titanium, zirconium, hafnium,vanadium, niobium or tantalum, preferably a metal atom of Group 4 of theperiodic table, such as titanium, zirconium or hafnium, more preferablyzirconium.

[0211] m is an integer of 1 to 2, preferably 2.

[0212] R¹ is an aliphatic or alicyclic hydrocarbon group.

[0213] Examples of the hydrocarbon groups include:

[0214] aliphatic hydrocarbon groups of 1 to 30 carbon atoms, such asmethyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl,tert-butyl, n-pentyl, tert-amyl, 1,2-dimethylpropyl, 1-ethylpropyl,isoamyl, 1-methylbutyl, 2-methylbutyl, neopentyl, n-hexyl,1,3-dimethylbutyl, 3,3-dimethylbutyl, n-heptyl, 1-ethylpentyl,1-methylhexyl, n-octyl, 1,5-dimethylhexyl, 2-ethylhexyl, 1-methylheptyl,tert-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl,n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl and n-octadecyl;and

[0215] alicyclic hydrocarbon groups of 3 to 30 carbon atoms, such ascyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, 2-methylcyclohexyl,2,2-dimethylcyclohexyl, 2,6-dimethylcyclohexyl,2,2,6,6-tetramethylcyclohexyl, adamantyl, cyclopropylmethyl,cyclobutylmethyl, cyclopentylmethyl and cyclohexylmethyl.

[0216] R¹ is preferably an aliphatic or alicyclic hydrocarbon grouprepresented by CH₂R′ or an alicyclic hydrocarbon group containing acarbon atom bonded to the N atom as a part of the alicyclic skeleton,and is particularly preferably an aliphatic or alicyclic hydrocarbongroup represented by CH₂R′.

[0217] R′ is an aliphatic or alicyclic hydrocarbon group, and examplesthereof include aliphatic hydrocarbon groups of 1 to 29 carbon atoms,such as methyl, ethyl, n-propyl, isopropyl, n-butyl, 2-methylpropyl,isobutyl, n-pentyl, neopentyl, n-hexyl, n-heptyl, 1-ethylpentyl,n-octyl, n-nonyl, n-decyl, n-undecyl, n dodecyl, n-tridecyl,n-tetradecyl, n-pentadecyl, n-hexadecyl and n-heptadecyl; and alicyclichydrocarbon groups of 3 to 29 carbon atoms, such as cyclopropyl,cyclobutyl, cyclopentyl and cyclohexyl. Of these, preferable as R′ is astraight-chain aliphatic hydrocarbon group of 1 to 17 carbon atoms.

[0218] Preferred examples of the alicyclic hydrocarbon groups containinga carbon atom bonded to the N atom as a part of the alicyclic skeletoninclude cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl,2-methylcyclohexyl, 2,2-dimethylcyclohexyl, 2,6-dimethylcyclohexyl,2,2,6,6-tetramethylcyclohexyl and adamantyl. Of these, cyclohexyl ismore preferable.

[0219] R² to R⁵ may be the same or different and are each a hydrocarbongroup, a hydrogen atom, a hydrocarbon-substituted silyl group, anoxygen-containing group, a nitrogen-containing group or asulfur-containing group.

[0220] Examples of the hydrocarbon groups include straight-chain orbranched alkyl groups of 1 to 30 carbon atoms, preferably 1 to 20 carbonatoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,sec-butyl, tert-butyl, neopentyl and n-hexyl; straight-chain or branchedalkenyl groups of 2 to 30 carbon atoms, preferably 2 to 20 carbon atoms,such as vinyl, allyl and isopropenyl; straight-chain or branched alkynylgroups of 2 to 30 carbon atoms, preferably 2 to 20 carbon atoms, such asethynyl and propargyl; cyclic saturated hydrocarbon groups of 3 to 30carbon atoms, preferably 3 to 20 carbon atoms, such as cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl and adamantyl; cyclic unsaturatedhydrocarbon groups of 5 to 30 carbon atoms, such as cyclopentadienyl,indenyl and fluorenyl; aryl groups of 6 to 30 carbon atoms, preferably 6to 20 carbon atom, such as phenyl, benzyl, naphthyl, biphenylyl,terphenylyl, phenanthryl and anthryl; and alkyl-substituted aryl groups,such as tolyl, isopropylphenyl, t-butylphenyl, dimethylphenyl anddi-t-butylphenyl.

[0221] In the above hydrocarbon groups, the hydrogen atom may bereplaced with a halogen, and examples of the hydrocarbon groups in whichthe hydrogen atom is replaced with a halogen include halogenatedhydrocarbon groups of 1 to 30 carbon atoms, preferably 1 to 20 carbonatoms, such as trifluoromethyl, pentafluorophenyl and chlorophenyl.

[0222] The above hydrocarbon groups maybe substituted with otherhydrocarbon groups, and examples of such hydrocarbon groups includearyl-substituted hydrocarbon groups, such as benzyl and cumyl.

[0223] Of the above groups, preferable are straight-chain or branchedalkyl groups of 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms,such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,sec-butyl, t-butyl, neopentyl and n-hexyl; aryl groups of 6 to 30 carbonatoms, preferably 6 to 20 carbon atom, such as phenyl, naphthyl,biphenylyl, terphenylyl, phenanthryl and anthryl; and substituted arylgroups wherein the above aryl groups are substituted with 1 to 5substituents such as halogen atoms, alkyl groups of 1 to 30 carbonatoms, preferably 1 to 20 carbon atoms, alkoxy groups of 1 to 30 carbonatoms, preferably 1 to 20 carbon atoms, aryl groups of 6 to 30 carbonatoms, preferably 6 to 20 carbon atoms or aryloxy groups of 6 to 30carbon atoms, preferably 6 to 20 carbon atoms.

[0224] Examples of the hydrocarbon-substituted silyl groups includemethylsilyl, dimethylsilyl, trimethylsilyl, ethylsilyl, diethylsilyl,triethylsilyl, diphenylmethylsilyl, triphenylsilyl, dimethylphenylsilyl,dimethyl-t-butylsilyl and dimethyl(pentafluorophenyl) silyl. Of these,preferable are methylsilyl, dimethylsilyl, trimethylsilyl, ethylsilyl,diethylsilyl, triethylsilyl, dimethylphenylsilyl and triphenylsilyl, andparticularly preferable are trimethylsilyl, triethylsilyl,triphenylsilyl and dimethylphenylsilyl.

[0225] The oxygen-containing group is a group containing 1 to 5 oxygenatoms, and does not include the later-described heterocyclic compoundresidue. Examples of the oxygen-containing groups include hydroxylgroup; alkoxy groups, such as methoxy, ethoxy, n-propoxy, isopropoxy,n-butoxy, isobutoxy and tert-butoxy; aryloxy groups, such as phenoxy,methylphenoxy, 2,6-dimethylphenoxy, 2,4,6-trimethylphenoxy andnaphthoxy; arylalkoxy groups, such as phenylmethoxy and phenylethoxy;acetoxy group; and carbonyl group.

[0226] The nitrogen-containing group is a group containing 1 to 5nitrogen atoms, and does not include the later-described heterocycliccompound residue. Examples of the nitrogen-containing groups includeamino groups, such as methylamino, dimethylamino, diethylamino,dipropylamino, dibutylamino, dicyclohexylamino, phenylamino,diphenylamino, ditolylamino, dinaphthylamino and methylphenylamino;imino groups, such as methylimino, ethylimino, propylimino, butyliminoand phenylimino; amido groups, such as acetamido, N-methylacetamido andN-methylbenzamido; imido groups, such as acetimido and benzimido; andnitro group.

[0227] The sulfur-containing group is a group containing 1 to 5 sulfuratoms, and does not include the later-described heterocyclic compoundresidue. Examples of the sulfur-containing groups include sulfonatogroups, such as methylsulfonato, trifluoromethanesulfonato,phenylsulfonato, benzylsulfonato, p-toluenesulfonato,trimethylbenzenesulfonato, triisobutylbenzenesulfonato,p-chlorobenzenesulfonato and pentafluorobenzenesulfonato; sulfinatogroups, such as methylsulfinato, phenylsulfinato, benzylsulfinato,p-toluenesulfinato, trimethylbenzenesulfinato andpentafluorobenzenesulfinato; alkylthio groups, such as methylthio andethylthio; and arylthio groups, such as phenylthio, methylphenylthio andnaphthylthio.

[0228] R⁶ is a hydrocarbon group or a hydrocarbon-substituted silylgroup.

[0229] Examples of the hydrocarbon groups preferable as R⁶ includestraight-chain or branched alkyl groups of 1 to 30 carbon atoms,preferably 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, neopentyl andn-hexyl; cyclic saturated hydrocarbon groups of 3 to 30 carbon atoms,preferably 3 to 20 carbon atoms, such as cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl and adamantyl; aryl groups of 6 to 30 carbonatoms, preferably 6 to 20 carbon atom, such as phenyl, benzyl, naphthyl,biphenylyl and triphenylyl; and groups wherein the above groups arefurther substituted with substituents such as alkyl groups of 1 to 30carbon atoms, preferably 1 to 20 carbon atoms, or aryl groups of 6 to 30carbon atoms, preferably 6 to 20 carbon atoms.

[0230] Examples of the hydrocarbon-substituted silyl groups preferableas R⁶ include methylsilyl, dimethylsilyl, trimethylsilyl, ethylsilyl,diethylsilyl, triethylsilyl, diphenylmethylsilyl, triphenylsilyl,dimethylphenylsilyl, dimethyl-t-butylsilyl anddimethyl(pentafluorophenyl)silyl. Of these, particularly preferable aretrimethylsilyl, triethylphenyl, diphenylmethylsilyl, isophenylsilyl,dimethylphenylsilyl, dimethyl-tert-butylsilyl anddimethyl(pentafluorophenyl)silyl.

[0231] In the present invention, R⁶ is particularly preferably abranched alkyl group of 3 to 30 carbon atoms, preferably 3 to 20 carbonatoms, such as isopropyl, isobutyl, sec-butyl, tert-butyl or neopentyl,a group wherein the hydrogen atom of the above branched alkyl group isreplaced with an aryl group of 6 to 30 carbon atoms, preferably 6 to 20carbon atoms, such as cumyl, or a cyclic saturated hydrocarbon group of3 to 30 carbon atoms, preferably 3 to 20 carbon atoms, such asadamantyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl; and isalso particularly preferably an aryl group of 6 to 30 carbon atoms,preferably 6 to 20 carbon atoms, such as phenyl, naphthyl, fluorenyl,anthranyl or phenanthryl, or a hydrocarbon-substituted silyl group.

[0232] Two or more groups of R¹ to R⁶, preferably neighboring groupsthereof, may he bonded to form an aliphatic ring, an aromatic ring or ahydrocarbon ring containing a hetero atom such as a nitrogen atom, andthese rings may further has a substituent.

[0233] n is a number satisfying a valence of M, specifically an integerof 2 to 4, preferably 2.

[0234] X is a hydrogen atom, a halogen atom, a hydrocarbon group, anoxygen-containing group, a sulfur-containing group, anitrogen-containing group, a boron-containing group, analuminum-containing group, a phosphorus-containing group, ahalogen-containing group, a heterocyclic compound residue, asilicon-containing group, a germanium-containing group or atin-containing group, and when n is 2 or greater, plural groupsindicated by X may be the same or different, and plural groups indicatedby X may be bonded to form a ring.

[0235] The halogen atom is fluorine, chlorine, bromine or iodine.

[0236] Examples of the hydrocarbon groups include the same groups aspreviously exemplified with respect to R¹ to R⁶. More specifically,there can be mentioned alkyl groups, such as methyl, ethyl, propyl,butyl, hexyl, octyl, nonyl, dodecyl and eicosyl; cycloalkyl groups of 3to 30 carbon atoms, such as cyclopentyl, cyclohexyl, norbornyl andadamantyl; alkenyl groups, such as vinyl, propenyl and cyclohexenyl;arylalkyl groups, such as benzyl, phenylethyl and phenylpropyl; and arylgroups, such as phenyl, tolyl, dimethylphenyl, trimethylphenyl,ethylphenyl, propylphenyl, biphenyl, naphthyl, methylnaphthyl, anthryland phenanthryl. These hydrocarbon groups include halogenatedhydrocarbon groups such as groups wherein at least one hydrogen ofhydrocarbon groups of 1 to 20 carbon atoms is replaced with a halogen.

[0237] The oxygen-containing group is a group containing 1 to 5 oxygenatoms, and does not include the later-described heterocyclic compoundresidue. Examples of the oxygen-containing groups include hydroxylgroup; alkoxy groups, such as methoxy, ethoxy, propoxy and butoxy;aryloxy groups, such as phenoxy, methylphenoxy, dimethylphenoxy andnaphthoxy; arylalkoxy groups, such as phenylmethoxy and phenylethoxy;acetoxy group; and carbonyl group.

[0238] The sulfur-containing group is a group containing 1 to 5 sulfuratoms, and does not include the later-described heterocyclic compoundresidue. Examples of the sulfur-containing groups include sulfonatogroups, such as methylsulfonato, trifluoromethanesulfonato,phenylsulfonato, benzylsulfonato, p-toluenesulfonato,trimethylbenzenesulfonato, triisobutylbenzenesulfonato,p-chlorobenzenesulfonato and pentafluorobenzenesulfonato; sulfinatogroups, such as methylsulfinato, phenylsulfinato, benzylsulfinato,p-toluenesulfinato, trimethylbenzenesulfinato andpentafluorobenzenesulfinato; alkylthio groups; and arylthio groups.

[0239] The nitrogen-containing group is a group containing 1 to 5nitrogen atoms, and does not include the later-described heterocycliccompound residue. Examples of the nitrogen-containing groups includeamino group; alkylamino groups, such as methylamino, dimethylamino,diethylamino, dipropylamino, dibutylamino and dicyclohexylamino; andarylamino or alkylarylamino groups, such as phenylamino, diphenylamino,ditolylamino, dinaphthylamino and methylphenylamino.

[0240] The boron-containing group is a group containing 1 to 5 boronatoms, and does not include the later-described heterocyclic compoundresidue. The boron-containing group is, for example, BR₄ (R is hydrogen,an alkyl group, an aryl group which may have a substituent, a halogenatom or the like).

[0241] The aluminum-containing group is, for example, AlR₄ (R ishydrogen, an alkyl group, an aryl group which may have a substituent, ahalogen atom or the like).

[0242] The phosphorus-containing group is a group containing 1 to 5phosphorus atoms, and does not include the later-described heterocycliccompound residue. Examples of the phosphorus-containing groups includetrialkylphosphine groups, such as trimethylphosphine, tributylphosphineand tricyclohexylphosphine; triarylphosphine groups, such astriphenylphosphine and tritolylphosphine; phosphite groups (phosphidogroups), such as melhylphosphite, ethylphosphite and phenylphosphite;phosphonic acid group; and phosphinic acid group.

[0243] Examples of the halogen-containing groups includefluorine-containing groups, such as PF₆ and BF₄; chlorine-containinggroups, such as ClO₄ and SbCl₆; and iodine-containing groups, such asIO₄.

[0244] The heterocyclic compound residue is a group having a cyclicstructure containing one or more hetero atoms. Examples of the heteroatoms include oxygen, nitrogen, sulfur, phosphorus and boron. Examplesof the cyclic structures include 3- to 18-membered rings. Of these,preferable are 4- to 7-membered rings, and more preferable are 5- to6-membered rings. Examples of the heterocyclic compound residues includeresidues of nitrogen-containing compounds such as pyrrole, pyridine,pyrimidine, quinoline and triazine, oxygen-containing compounds such asfuran and pyran, and sulfur-containing compounds such as thiophene, andgroups wherein these heterocyclic compound residues are furthersubstituted with substituents such as alkyl groups of 1 to 30 carbonatoms, preferably 1 to 20 carbon atoms, or alkoxy groups.

[0245] Examples of the silicon-containing groups includehydrocarbon-substituted silyl groups, such as phenylsilyl,diphenylsilyl, trimethylsilyl, triethylsilyl, tripropylsilyl,tricyclohexylsilyl, triphenylsilyl, methyldiphenylsilyl, tritolylsilyland trinaphthylsilyl; hydrocarbon-substituted silyl ether groups, suchas trimethylsilyl ether; silicon-substituted alkyl groups, such astrimethylsilylmethyl; and silicon-substituted aryl groups, such astrimethylsilylphenyl.

[0246] Examples of the germanium-containing groups include groupswherein silicon is replaced with germanium in the above-mentionedsilicon-containing groups.

[0247] Examples of the tin-containing groups include groups whereinsilicon is replaced with tin in the above-mentioned silicon-containinggroups.

[0248] Examples of the transition metal compounds represented by theformula (I) are given below, but the transition metal compounds are notlimited thereto.

[0249] In the above examples, Me denotes a methyl group, Et denotes anethyl group, nPr denotes a n-propyl group, iPr denotes an isopropylgroup, nBu denotes a n-butyl group, tBu denotes a t-butyl group, nPentyldenotes a n-pentyl group, nHexyl denotes a n-hexyl group, nHeptyldenotes a n-heptyl group, nOctyl denotes a n-Octyl group, nNonyl denotesa n-nonyl group, nDecyl denotes a n-decyl group, nUndecyl denotes an-undecyl group, nDodecyl denotes a n-dodecyl group, nOctadecyl denotesa n-octadecyl group, and Ph denotes a phenyl group.

[0250] Also employable are transition metal compounds wherein thezirconium atom is replaced with a metal other than zirconium, such astitanium or hafnium, in the above compounds.

[0251] The process for preparing the transition metal compound (B)represented by the formula (I) is not specifically restricted, and thetransition metal compound (B) can be prepared by, for example, thefollowing process.

[0252] First, a compound (referred to as a “ligand precursor”hereinafter) which becomes a ligand in the resulting transition metalcompound represented by the formula (I) is obtained by reacting asalicylaldehyde compound with a primary amine compound of the formulaR¹—NH₂ (R¹ has the same meaning as in the formula (I)), such as ananiline compound or an alkylamine compound.

[0253] More specifically, both of the compounds are dissolved in asolvent. As the solvent, any solvent usually used for such reaction isemployable, and particularly, an alcohol solvent such as methanol orethanol or a hydrocarbon solvent such as toluene is preferable. Then,the resulting solution is stirred for about 1 to 48 hours at roomtemperature or under reflux, whereby the corresponding ligand precursoris obtained in excellent yield.

[0254] In the synthesis of the ligand precursor, an acid catalyst, suchas formic acid, acetic acid or toluenesulfonic acid, may be used as thecatalyst. The reaction can be effectively promoted by the use ofmolecular sieves, magnesium sulfate or sodium sulfate as a dehydratingagent or by conducting dehydration through the Dien and Stark method.

[0255] Then, the ligand precursor obtained as above is reacted with ametallic compound represented by MX_(k) (M and X have the same meaningsas those of M and X in the formula (I), and K is a number satisfying avalance of M), whereby the corresponding transition metal compound canbe synthesized.

[0256] More specifically, the synthesized ligand precursor is dissolvedin a solvent and if necessary contacted with a base to prepare aphenoxide salt, then the solution or the salt is mixed with a metalliccompound such as a metallic halide or a metallic alkylate, and themixture is stirred for about 1 to 48 hours at a temperature of −78° C.to room temperature or under reflux. As the solvent, any solvent usuallyused for such reaction is employable, and particularly, a polar solventsuch as ether or tetrahydrofuran (THF) or a hydrocarbon solvent such astoluene is preferably used. As the base for preparing a phenoxide salt,a metallic salt, e.g., a lithium salt such as n-butyllithium or a sodiumsalt such as sodium hydride, or an organic base such as triethylamine orpyridine is preferable.

[0257] Depending upon the properties of the compound, the ligandprecursor is directly reacted with the metallic compound withoutpreparing the phenoxide salt, whereby the corresponding transition metalcompound can also be synthesized.

[0258] Further, it is possible to replace the metal M in the resultingtransition metal compound with another transition metal in aconventional manner. When any one of R¹ to R⁶ is a hydrogen atom, asubstituent other than a hydrogen atom can be introduced in any stage ofthe synthesis process.

[0259] The reaction solution of the ligand precursor and the transitionmetal M-containing compound can be used as it is without isolating thetransition metal compound (B) from the solution.

[0260] The transition metal compounds (B) represented by the formula (T)are used singly or in combination of two or more kinds.

(C-1) Organometallic Compound

[0261] Examples of the organometallic compounds (C-1) employable in theinvention include the below-described organometallic compoundscontaining metals of Group 1, Group 2, Group 12 and Group 13 of theperiodic table.

[0262] (C-1a) Organoaluminum compound represented by the followingformula:

R^(a) _(m)Al(OR^(b))_(n)H_(p)X_(q)

[0263] wherein R^(a) and R^(b) may be the same or different and are eacha hydrocarbon group of 1 to 15 carbon atoms, preferably 1 to 4 carbonatoms; X is a halogen atom; and m, n, p and q are numbers satisfying theconditions of 0<m≦3, 0≦n<3, 0≦p<3, 0≦q<3 and m+n+p+q=3.

[0264] (C-1b) Alkyl complex compound comprising a Group 1 metal of theperiodic table and aluminum and represented by the following formula;

M²AlR^(a) ₄

[0265] wherein M² is Li, Na or K; and R^(a) is a hydrocarbon group of 1to 15 carbon atoms, preferably 1 to 4 carbon atoms.

[0266] (C-1c) Dialkyl compound containing a Group 2 or Group 12 metal ofthe periodic table and represented by the following formula:

R^(a)R^(b)M³

[0267] wherein R^(a) and R^(b) may be the same or different and are eacha hydrocarbon group of 1 to 15 carbon atoms, preferably 1 to 4 carbonatoms; and M³ is Mg, Zn or Cd.

[0268] Examples of the organoaluminum compounds (C-1a) include:

[0269] an organoaluminum compound represented by the following formula:

R^(a) _(m)Al(OR^(b))_(3-m)

[0270]  wherein R^(a) and R^(b) may be the same or different and areeach a hydrocarbon group of 1 to 15 carbon atoms, preferably 1 to 4carbon atoms; and m is preferably a number satisfying the condition of1.5≦m≦3;

[0271] an organoaluminum compound represented by the following formula:

R^(a) _(m)AlX_(3-m)

[0272]  wherein R^(a) is a hydrocarbon group of 1 to 15 carbon atoms,preferably 1 to 4 carbon atoms; X is a halogen atom; and m is preferablya number satisfying the condition of 0<m<3;

[0273] an organoaluminum compound represented by the following formula:

R^(a) _(m)AlH_(3-m)

[0274]  wherein R^(a) is a hydrocarbon group of 1 to 15 carbon atoms,preferably 1 to 4 carbon atoms; and m is preferably a number satisfyingthe condition of 2≦m<3;

[0275] and

[0276] an organoaluminum compound represented by the following formula:

R^(a) _(m)Al(OR^(b))_(n)X_(q)

[0277]  wherein R^(a) and R^(b) may be the same or different and areeach a hydrocarbon group of 1 to 15 carbon atoms, preferably 1 to 4carbon atoms; X is a halogen atom; and m, n and q are numbers satisfyingthe conditions of 0<m≦3, 0≦n<3, 0≦q<3 and m+n+q=3.

[0278] Particular examples of the organoaluminum compounds (C-1a)include:

[0279] tri-n-alkylaluminums, such as trimethylaluminum,triethylaluminum, tri-n-butylaluminum, tripropylaluminum,tripentylaluminum, trihexylaluminum, trioctylaluminum andtridecylaluminum;

[0280] tri-branched-chain alkylaluminums, such as triisopropylaluminum,triisobutylaluminum, tri-sec-butylaluminum, tri-tert-butylaluminum,tri-2-methylbutylaluminum, tri-3-methylbutylaluminum,tri-2-methylpentylaluminum, tri-3-methylpentylaluminum,tri-4-methylpentylaluminum, tri-2-methylhexylaluminum,tri-3-methylhexylaluminum and tri-2-ethylhexylaluminum;

[0281] tricycloalkylaluminums, such as tricyclohexylaluminum andtricyclooctylaluminum;

[0282] triarylaluminums, such as triphenylaluminum and tritolylaluminum;

[0283] dialkylaluminum hydrides, such as diisobutylaluminum hydride;

[0284] trialkenylaluminums represented by (i-C₄H₉)_(x)Al_(y)(C₅H₁₀)₂(wherein x, y and z are each a positive number, and z≧2x) or the like,such as isoprenylaluminum;

[0285] alkylaluminum alkoxides, such as isobutylaluminum methoxide,isobutylaluminum ethoxide and isobutylaluminum isopropoxide;

[0286] dialkylaluminum alkoxides, such as dimethylaluminum methoxide,diethylaluminum ethoxide and dibutylaluminum butoxide;

[0287] alkylaluminum sesquialkoxides, such as ethylaluminumsesquiethoxide and butylaluminum sesquibutoxide;

[0288] partially alkoxylated alkylaluminums having an averagecomposition represented by R^(a) _(2.5)Al(OR^(b))_(0.5) or the like:

[0289] dialkylaluminum aryloxides, such as diethylaluminum phenoxide,diethylaluminum(2,6-di-t-butyl-4-methylphenoxide),ethylaluminumbis(2,6-di-t-butyl-4-methylphenoxide),diisobutylalumium(2,6-di-t-butyl-4-methylphenoxide) andisobutylaluminumbis(2,6-di-t-butyl-4-methylphenoxide);

[0290] dialkylaluminum halides, such as dimethylaluminum chloride,diethylaluminum chloride, dibutylaluminum chloride, diethylaluminumbromide and diisobutylaluminum chloride;

[0291] alkylaluminum sesquihalides, such as ethylaluminumsesquichloride, butylaluminum sesquichloride and ethylaluminumsesquibromide,

[0292] partially halogenated alkylaluminums, such as ethylaluminumdichloride, propylaluminum dichloride and butylaluminum dibromide;

[0293] dialkylaluminum hydrides, such as diethylaluminum hydride anddibutylaluminum hydride;

[0294] partially hydrogenated alkylaluminums, e.g., alkylaluminumdihydrides, such as ethylaluminum dihydride and propylaluminumdihydride; and

[0295] partially alkoxylated and halogenated alkylaluminums, such asethylaluminum ethoxychloride, butylaluminum butoxychloride andethylaluminum ethoxybromide.

[0296] Also employable is a compound analogous to the organoaluminumcompound (C-1a), such as an organoaluminum compound wherein two or morealuminum compounds are combined through a nitrogen atom. An example ofsuch compound is (C₂H₅)₂AlN(C₂H₅)Al(C₂H₅)₂.

[0297] Examples of the organoaluminum compounds (C-1b) includeLiAl(C₂H₅)₄ and LiAl(C₇H₁₅)₄.

[0298] Other compounds, such as methyllithium, ethyllithium,propyllithium, butyllithium, methylmagnesium bromide, methylmagnesiumchloride, ethylmagnesium bromide, ethylmagnesium chloride,propylmagnesium bromide, propylmagnesium chloride, butylmagnesiumbromide, butylmagnesium chloride, dimethylmagnesium, diethylmagnesium,dibutylmagnesium and butylethylmagnesium, are also employable as theorganometallic compounds (C-1).

[0299] Combinations of compounds capable of producing theabove-mentioned organoaluminum compounds in the polymerization system,e.g., a combination of halogenated aluminum and alkyllithium and acombination of halogenated aluminum and alkylmagnesium, are alsoemployable.

[0300] Of the organometallic compounds (C-1) mentioned above,organoaluminum compounds are preferable.

[0301] The organometallic compounds (C-1) mentioned above are usedsingly or in combination of two or more kinds.

(C-2) Organoaluminum Oxy-Compound

[0302] The organoaluminum oxy-compound (B-2) may be a hitherto knownaluminoxane or may be such a benzene-insoluble organoaluminumoxy-compound as exemplified in Japanese Patent Laid-Open Publication No.78687/1990.

[0303] The hitherto known aluminoxane can be prepared by, for example,the following processes, and is generally obtained as a hydrocarbonsolvent solution.

[0304] (1) An organoaluminum compound such as trialkylaluminum is addedto a hydrocarbon medium suspension of a compound containing adsorptionwater or a salt containing water of crystallization, e.g., magnesiumchloride hydrate, copper sulfate hydrate, aluminum sulfate hydrate,nickel sulfate hydrate or cerous chloride hydrate, to allow theorganoaluminum compound to react with the adsorption water or the waterof crystallization.

[0305] (2) Water, ice or water vapor is allowed to directly act on anorganoaluminum compound such as trialkylaluminum in a medium such asbenzene, toluene, ethyl ether or tetrahydrofuran.

[0306] (3) An organotin oxide such as dimethyltin oxide or dibutyltinoxide is allowed to react with an organoaluminum compound such astrialkylaluminum in a medium such as decane, benzene or toluene.

[0307] The aluminoxane may contain a small amount of an organometalliccomponent. Further, it is possible that the solvent or the unreactedorganoaluminum compound is removed from the recovered solution ofaluminoxane by distillation and the remainder is redissolved in asolvent or suspended in a poor solvent for aluminoxane.

[0308] Examples of the organoaluminum compounds used for preparing thealuminoxane include the same organoaluminum compounds as previouslydescribed with respect to the organoaluminum compound (C-1a).

[0309] Of these, preferable are trialkylaluminums andtricycloalkylaluminums, and particularly preferable istrimethylaluminum. The organoaluminum compounds are used singly or incombination of two or more kinds.

[0310] Examples of the solvents used for preparing the aluminoxaneinclude aromatic hydrocarbons, such as benzene, toluene, xylene, cumeneand cymene; aliphatic hydrocarbons, such as pentane, hexane, heptane,octane, decane, dodecane, hexadecane and octadecane; alicyclichydrocarbons, such as cyclopentane, cyclohexane, cyclooctane andmethylcyclopentane; petroleum fractions, such as gasoline, kerosine andgas oil; and halides of these aromatic, aliphatic and alicyclichydrocarbons (e.g., chlorides and bromides thereof). Also employable areethers such as ethyl ether and tetrahydrofuran. Of the solvents,particularly preferable are aromatic hydrocarbons and aliphatichydrocarbons.

[0311] The benzene-insoluble organoaluminum oxy-compound is preferablyan organoaluminum oxy-compound containing an Al component which issoluble in benzene at 60° C. in an amount of usually not more than 10%,preferably not more than 5%, particularly preferably not more than 2%,in terms of Al atom. That is, the benzene-insoluble organoaluminumoxy-compound is preferably insoluble or sparingly soluble in benzene.

[0312] The organoaluminum oxy-compound employable may be anorganoaluminum oxy-compound containing boron and represented by thefollowing formula (II):

[0313] wherein R¹⁰ is a hydrocarbon group of 1 to 10 carbon atoms; andeach R¹¹ may be the same or different and is a hydrogen atom, a halogenatom or a hydrocarbon group of 1 to 10 carbon atoms.

[0314] The organoaluminum compound containing boron and represented bythe formula (II) can be prepared by allowing an alkylboronic acidrepresented by the following formula (III) to react with anorganoaluminum compound in an inert solvent at a temperature of −80° C.to room temperature for 1 minute to 24 hours in an inert gas atmosphere.

R¹⁰—B—(OH)₂  (III)

[0315] wherein R¹⁰ is the same group as described above.

[0316] Examples of the alkylboronic acids represented by the formula(III) include methylboronic acid, ethylboronic acid, isopropylboronicacid, n-propylboronic acid, n-butylboronic acid, isobutylboronic acid,n-hexylboronic acid, cyclohexylboronic acid, phenylboronic acid,3,5-difluoroboronic acid, pentafluorophenylboronic acid and3,5-bis(trifluoromethyl)phenylboronic acid. Of these, preferable aremethylboronic acid, n-butylboronic acid, isobutylboronic acid,3,5-difluorophenylboronic acid and pentafluorophenylboronic acid. Thesealkylboronic acids are used singly or in combination of two or morekinds.

[0317] Examples of the organoaluminum compounds to be reacted with thealkylboronic acid include the same organoaluminum compounds aspreviously described with respect to the organoaluminum compound (C-1a).

[0318] Of these, preferable are trialkylaluminums andtricycloalkylaluminums, and particularly preferable aretrimethylaluminum, triethylaluminum and triisobutylaluminum. Theseorganoaluminum compounds are used singly or in combination of two ormore kinds.

[0319] The organoaluminum oxy-compounds (B-2) mentioned above are usedsingly or in combination of two or more kinds.

(C-3) Compound Which Reacts with the Transition Metal Compound to FormIon Pair

[0320] Examples of the compounds (C-3) which react with the transitionmetal compound (A) or the transition metal compound (B) to form an ionpair (referred to as “ionizing ionic compound” hereinafter) includeLewis acid, an ionic compound, a borane compound and a carboranecompound described in Japanese Patent Laid-Open Publications No.501950/1989, No. 502036/1989, No. 19005/1991, No. 179006/1991, No.207703/1991 and No. 207704/1991, and U.S. Pat. No. 5,321,106. Aheteropoly compound and an isopoly compound are also available.

[0321] The Lewis acid is, for example, a compound represented by BR₃ (Ris fluorine or a phenyl group which may have a substituent such asfluorine, methyl or trifluoromethyl). Examples of such compounds includetrifluoroboron, triphenylboron, tris(4-fluorophenyl)boron,tris(3,5-difluorophenyl)boron, tris(4-fluoromethylphenyl)boron,tris(pentafluorophenyl)boron, tris(p-tolyl)boron, tris(o-tolyl)boron andtris(3,5-dimethylphenyl)boron.

[0322] The ionic compound is, for example, a compound represented by thefollowing formula (IV).

[0323] In the above formula, R¹² is H⁺, carbonium cation, oxoniumcation, ammonium cation, phosphonium cation, cycloheptyltrienyl cation,ferrocenium cation having a transition metal, or the like.

[0324] R¹³ to R¹⁶ may be the same or different and are each an organicgroup, preferably an aryl group or a substituted aryl group.

[0325] Examples of the carbonium cations include tri-substitutedcarbonium cations, such as triphenylcarbonium cation,tri(methylphenyl)carbonium cation and tri(dimethylphenyl)carboniumcation.

[0326] Examples of the ammonium cations include trialkylammoniumcations, such as trimethylammonium cation, triethylammonium cation,tripropylammonium cation, tributylammonium cation andtri(n-butyl)ammonium cation; N,N-dialkylanilinium cations, such asN,N-dimethylanilinium cation, N,N-diethylanilinium cation andN,N-2,4,6-pentamethylanilinium cation; and dialkylammonium cations, suchas di(isopropyl)ammonium cation and dicyclohexylammonium cation.

[0327] Examples of the phosphonium cations include triarylphosphoniumcations, such as triphenylphosphonium cation,tri(methylphenyl)phosphonium cation and tri(dimethylphenyl)phosphoniumcation.

[0328] R¹² is preferably carbonium cation, ammonium cation or the like,particularly preferably triphenylcarbonium cation, N,N-dimethylaniliniumcation or N,N-diethylanilinium cation.

[0329] Also available as the ionic compound is a trialkyl-substitutedammonium salt, an N,N-dialkylanilinium salt, a dialkylammonium salt or atriarylphosphonium salt.

[0330] Examples of the trialkyl-substituted ammonium salts includetriethylammoniumtetra(phenyl)boron, tripropylammoniumtetra(phenyl)boron,tri(n-butyl)ammoniumtetra(phenyl)boron,trimethylammoniumtetra(p-tolyl)boron,trimethylammoniumtetra(o-tolyl)boron,tri(n-butyl)ammoniumtetra(pentafluorophenyl)boron,tripropylammoniumtetra(o,p-dimethylphenyl)boron,tri(n-butyl)ammoniumtetra(m,m-dimethylphenyl)boron,tri(n-butyl)ammoniumtetra(p-trifluoromethylphenyl)boron, tri(n-butyl)ammoniumtetra(3,5-ditrifluoromethylphenyl)bor on andtri(n-butyl)ammoniumtetra(o-tolyl)boron.

[0331] Examples of the N,N-dialkylanilinium salts includeN,N-dimethylaniliniumtetra(phenyl)boron,N,N-diethylaniliniumtetra(phenyl)boron andN,N-2,4,6-pentamethylaniliniumtetra(phenyl)boron.

[0332] Examples of the dialkylammonium salts includedi(1-propyl)ammoniumtetra(pentafluorophenyl)boron anddicyclohexylammoniumtetra(phenyl)boron.

[0333] Further employable as the ionic compound istriphenylcarbeniumtetrakis(pentafluorophenyl)borate,N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate,ferroceniumtetra(pentafluorophenyl)borate,triphenylcarbeniumpentaphenylcyclopentadienyl complex,N,N-diethylaniliniumpentaphenylcyclopentadienyl complex or a boroncompound represented by the following formula (V) or (VI).

[0334] wherein Et denotes an ethyl group.

[0335] Examples of the borane compounds include decaborane (14) salts ofanions, such as bis[tri (n-butyl)ammonium]nonaborate,bis[tri(n-butyl)ammonium]decaborate,bis[tri(n-butyl)ammonium]undecaborate,bis[tri(n-butyl)ammonium]dodecaborate,bis[tri(n-butyl)ammonium]decachlorodecaborate andbis[tri(n-butyl)ammonium]dodecachlorododecaborate; and salts of metallicborane anions, such astri(n-butyl)ammoniumbis(dodecahydridododecaborate)cobalta te(III) andbis[tri(n-butyl)ammonium]bis-(dodecahydridododecaborate)n ickelate(III).

[0336] Examples of the carborane compounds include: salts of anions,such as 4-carbanonaborane(14), 1,3-dicarbanonaborane(13),6,9-dicarbadecaborane(14), dodecahydrido-1-phenyl-1,3-dicarbanonaborane,dodecahydrido-1-methyl-1,3-dicarbanonaborane,undecahydrido-1,3-dimethyl-1,3-dicarbanonaborane,7,8-dicarbaundecaborane(13), 2,7-dicarbaundecaborane(13),undecahydrido-7,8-dimethyl-7,8-dicarbaundecaborane,dodecahydrido-11-methyl-2,7-dicarbaundecaborane, tri(n-butyl)ammonium-1-carbadecaborate,tri(n-butyl)ammonium-1-carbaundecaborate,tri(n-butyl)ammonium-1-carbadodecaborate,tri(n-butyl)ammonium-1-trimethylsilyl-1-carbadecaborate,tri(n-butyl)ammoniumbromo-1-carbadodecaborate,tri(n-butyl)ammonium-6-carbadecaborate(14),tri(n-butyl)ammonium-6-carbadecaborate(12),tri(n-butyl)ammonium-7-carbaundecaborate(13),tri(n-butyl)ammonium-7,8-dicarbaundecaborate(12),tri(n-butyl)ammonium-2,9-dicarbaundecaborate(12),tri(n-butyl)ammoniumdodecahydrido-8-methyl-7,9-dicarbaund ecaborate,tri(n-butyl)ammoniumundecahydrido-8-ethyl-7,9-dicarbaunde caborate,tri(n-butyl)ammoniumundecahydrido-8-butyl-7,9-dicarbaunde caborate,tri(n-butyl)ammoniumundecahydrido-8-allyl-7,9-dicarbaunde caborate,tri(n-butyl)ammoniumundecahydrido-9-trimethylsilyl-7,8-dicarbaundecaborate andtri(n-butyl)ammoniumundecahydrido-4,6-dibromo-7-carbaunde caborate; andsalts of metallic carborane anions, such astri(n-butyl)ammoniumbis(nonahydrido-1,3-dicarbanonaborate)cobaltate(III),tri(n-butyl)ammoniumbis(undecahydrido-7,8-dicarbaundecaborate)ferrate(III)tri(n-butyl)ammoniumbis(undecahydrido-7,8-dicarbaundecaborate)cobaltate(III),tri(n-butyl)ammoniumbis(undecahydrido-7,8-dicarbaundecaborate)nickelate(III),tri(n-butyl)ammoniumbis(undecahydrido-7,8-dicarbaundecaborate)cuprate(III),tri(n-butyl)ammoniumbis(undecahydrido-7,8-dicarbaundecaborate)aurate(III),tri(n-butyl)ammoniumbis(nonahydrido-7,8-dimethyl-7,8-dicarbaundecaborate)ferrate(III),tri(n-butyl)ammoniumbis(nonahydrido-7,8-dimethyl-7,8-dicarbaundecaborate)chromate(III),tri(n-butyl)ammoniumbis(tribromooctahydrido-7,8-dicarbaundecaborate)cobaltate(III),tris[tri(n-butyl)ammonium]bis(undecahydrido-7-carbaundecaborate)chromate(III),bis[tri(n-butyl)ammonium]bis(undecahydrido-7-carbaundecaborate)manganate(IV),bis[tri(n-butyl)ammonium]bis(undecahydrido-7-carbaundecaborate)cobaltate(III) andbis[tri(n-butyl)ammonium]bis(undecahydrido-7-carbaundecaborate)nickelate(IV).

[0337] The heteropoly compound comprises an atom selected from silicon,phosphorus, titanium, germanium, arsenic and tin and one or more atomsselected from vanadium, niobium, molybdenum and tungsten. Examples ofsuch compounds include phosphovanadic acid, germanovanadic acid,arsenovanadic acid, phosphoniobic acid, germanoniobic acid,silicomolybdic acid, phosphomolybdic acid, titanomolybdic acid,germanomolybdic acid, arsenomolybdic acid, stannomolybdic acid,phosphotungstic acid, germanotungstic acid, stannotungstic acid,phosphomolybdovanadic acid, phosphotungstovanadic acid,germanotungstovanadic acid, phosphomolybdotungstovanadic acid,germanomolybdotungstovanadic acid, phosphomolybdotungstic acid,phosphomolybdoniobic acid, and salts of these acids, e.g., salts ofthese acids and metals of Group 1 or Group 2 of the periodic table suchas lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium,calcium, strontium and barium, and organic salts such as triphenylethylsalt.

[0338] The ionizing ionic compounds (C-3) mentioned above are usedsingly or in combination of two or more kinds.

[0339] In the olefin polymerization catalyst of the invention, thebelow-described carrier (D) can be used if necessary, in addition to thetransition metal compound (A), the transition metal compound (B) and atleast one compound (C) selected from the organometallic compound (C-1),the organoaluminum oxy-compound (C-2) and the ionizing ionic compound(C-3).

(D) Carrier

[0340] The carrier (D) is an inorganic or organic compound and is agranular or particulate solid. As the inorganic compound, a porousoxide, an inorganic chloride, clay, a clay mineral or an ion-exchangelayered compound is preferable.

[0341] Examples of the porous oxides employable in the invention includeSiO₂, Al₂O₃, MgO, ZrO, TiO₂, B₂O₃, CaO, ZnO, BaO, ThO₂, and complexcompounds or mixtures containing these oxides, such as natural orsynthetic zeolite, SiO₂—MgO, SiO₂—Al₂O₃, SiO₂—TiO₂, SiO₂—V₂O₅,SiO₂—Cr₂O₃ and SiO₂—TiO₂—MgO. Of these, preferable are compounds eachcontaining SiO₂ and/or Al₂O₃ as the main component.

[0342] The inorganic oxides may contain small amounts of carbonate,sulfate, nitrate and oxide components, such as Na₂CO₃, K₂CO₃, CaCO₃,MgCO₃, Na₂SO₄, Al₂(SO₄)₃, BaSO₄, KNO₃, Mg(NO₃)₂, Al(NO₃)₃, Na₂O, K₂O andLi₂O.

[0343] Although the porous oxides differ in their properties dependingupon the type and the preparation thereof, the carrier preferably usedin the invention desirably has a particle diameter of 10 to 300 μm,preferably 20 to 200 μm, a specific surface area of 50 to 1,000 m²/g,preferably 100 to 700 m²/g, and a pore volume of 0.3 to 3.0 cm³/g.According to the necessity, the carrier is calcined at 100 to 1,000° C.,preferably 150 to 700° C., prior to use.

[0344] Examples of the inorganic chlorides employable in the inventioninclude MgCl₂, MgBr₂, MnCl₂ and MnBr₂. The inorganic chloride may beused as it is, or may be used after pulverized by a ball mill or anoscillating mill. Also employable is a precipitate in the form of fineparticles obtained by dissolving the inorganic chloride in a solventsuch as an alcohol and then conducting precipitation using aprecipitant.

[0345] The clay is usually constituted mainly of a clay mineral. Theion-exchange layered compound is a compound having a crystal structurewherein planes formed by ionic bonding or the like are laminated inparallel to one another with a weak bond strength, and the ionscontained therein are exchangeable. Most of clay minerals areion-exchange layered compounds. The clay, the clay minerals and theion-exchange layered compounds employable in the invention are notlimited to natural ones but include synthetic ones.

[0346] Examples of such clay, clay minerals and ion-exchange layeredcompounds include clay, clay minerals and ion crystalline compoundshaving layered crystal structures such as hexagonal closest packingtype, antimony type, CdCl₂ type and CdI₂ type.

[0347] Particular examples of the clay and the clay minerals includekaolin, bentonite, kibushi clay, gairome clay, allophane, hisingerite,pyrophyllite, mica, montmorillonite, vermiculite, chlorite,palygorskite, kaolinite, nacrite, dickite and halloysite. Particularexamples of the ion-exchange layered compounds include crystalline acidsalts of polyvalent metals, such as α-Zr(HAsO₄)₂.H₂O, α-Zr(HPO₄)₂,α-Zr(KPO₄)₂.3H₂O, α-Ti(HPO₄)₂, α-Ti(HAsO₄)₂.H₂O, α-Sn(HPO₄)₂.H₂O,γ-Zr(HPO₄)₂, γ-Ti(HPO₄)₂ and γ-Ti(NH₄PO₄)₂.H₂O,

[0348] The clay, the clay minerals and the ion-exchange layeredcompounds are preferably those having a pore volume, as measured onpores having a radius of not less than 20 Å by a mercury penetrationmethod, of not less than 0.1 cc/g, and are particularly preferably thosehaving a pore volume of 0.3 to 5 cc/g. The pore volume is measured onthe pores having a radius of 20 to 3×10⁴ Å by a mercury penetrationmethod using a mercury porosimeter.

[0349] If a compound having a pore volume, as measured on pores having aradius of not less than 20 Å, of less than 0.1 cc/g is used as thecarrier, high polymerization activity tends to be hardly obtained.

[0350] It is preferable to subject the clay and the clay minerals tochemical treatments. Any of surface treatments to remove impurities fromthe surface and treatments having an influence on the crystal structureof the clay is employable.

[0351] Examples of such chemical treatments include acid treatment,alkali treatment, salt treatment and organic substance treatment. Theacid treatment contributes to not only removing impurities from thesurface but also eluting cations such as Al, Fe and Mg present in thecrystal structure to increase the surface area. The alkali treatmentdestroys crystal structure of clay to bring about change in thestructure of the clay. The salt treatment and the organic substancetreatment can produce ionic complex, molecular complex, organicderivative or the like and change the surface area or the distancebetween layers.

[0352] The ion-exchange layered compound may be a layered compound inwhich the exchangeable ions between layers have been exchanged withother large and bulky ions utilizing ion exchange properties to enlargethe distance between the layers. The bulky ion plays a pillar-like rollto support the layer structure and is usually called a “pillar”.Introduction of other substances between layers of a layered compound iscalled “intercalation”. Examples of the guest compounds to beintercalated include cationic inorganic compounds, such as TiCl₄ andZrCl₄; metallic alkoxides, such as Ti(OR)₄, Zr(OR)₄, PO(OR)₃ and B(OR)₃(R is a hydrocarbon group or the like); and metallic hydroxide ions,such as [Al₁₃O₄(OH)₂₄]⁷⁺, [Zr₄(OH)₁₄]²⁺, and [Fe₃O(OCOCH₃)₆]⁺. Thesecompounds are used singly or in combination of two or more kinds.

[0353] The intercalation of these compounds may be carried out in thepresence of a polymerization product obtained by hydrolysis of ametallic alkoxide such as Si(OR)₄, Al(OR)₃ or Ge(OR)₄ (R is ahydrocarbon group or the like) or in the presence of a colloidalinorganic compound such as SiO₂. Examples of the pillars include oxidesproduced by intercalation of the above-mentioned metallic hydroxide ionsbetween layers, followed by dehydration under heating.

[0354] The clay, clay minerals and ion-exchange layered compoundsmentioned above may be used as they are, or may be used after subjectedto a treatment of ball milling, sieving or the like. Moreover, they maybe used after subjected to water adsorption or dehydration underheating. The clay, clay minerals and ion-exchange layered compounds maybe used singly or in combination of two or more kinds.

[0355] Of the above-mentioned materials, preferable are clay and clayminerals, and particularly preferable are montmorillonite, vermiculite,pectolite, taeniolite and synthetic mica.

[0356] The organic compound is, for example, a granular or particulatesolid having a particle diameter of 10 to 300 μm. Examples of suchcompounds include (co)polymers produced using as a main ingredient anα-olefin of 2 to 14 carbon atoms such as ethylene, propylene, 1-buteneor 4-methyl-1-pentene, (co)polymers produced using as a main ingredientvinylcyclohexane or styrene, and modification products thereof.

[0357] The olefin polymerization catalyst may further contain thebelow-described specific organic compound component (E) if necessary, inaddition to the transition metal compound (A) (component (A)), thetransition metal compound (B) (component (B)), at least one compound (C)(component (C)) selected from the organometallic compound (C-1), theorganoaluminum oxy-compound (C-2) and the ionizing ionic compound (C-3),and the carrier (C) optionally used.

(E) Organic Compound Component

[0358] The organic compound component (E) is used, if necessary, for thepurpose of improving polymerizability and properties of the resultingpolymer. Examples of the organic compounds include alcohols, phenoliccompounds, carboxylic acids, phosphorus compounds and sulfonates.

[0359] As the alcohols and the phenolic compounds, those represented byR²¹—OH (R²¹ is a hydrocarbon group of 1 to 50 carbon atoms or ahalogenated hydrocarbon group of 1 to 50 carbon atoms) are usually used.The alcohols are preferably those of the above formula wherein R²¹ is ahalogenated hydrocarbon group. The phenolic compounds are preferablythose wherein the α,α′-positions of the hydroxyl group are substitutedwith hydrocarbons of 1 to 20 carbon atoms.

[0360] As the carboxylic acids, those represented by R²²—COOH (R²² is ahydrocarbon group of 1 to 50 carbon atoms or a halogenated hydrocarbongroup of 1 to 50 carbon atoms, preferably a halogenated hydrocarbongroup of 1 to 50 carbon atoms) are usually used.

[0361] As the phosphorus compounds, phosphoric acids having P—O—H bond,phosphates having P—OR bond or P═O bond and phosphine oxide compoundsare preferably used.

[0362] As the sulfonates, those represented by the following formula(VII) are usually used.

[0363] In the above formula, M is an atom of Group 1 to Group 14 of theperiodic table.

[0364] R²³ is a hydrogen atom, a hydrocarbon group of 1 to 20 carbonatoms or a halogenated hydrocarbon group of 1 to 20 carbon atoms.

[0365] X is a hydrogen atom, a halogen atom, a hydrocarbon group of 1 to20 carbon atoms or a halogenated hydrocarbon group of 1 to 20 carbonatoms.

[0366] m is an integer of 1 to 7, and n is a number of 1≦n≦7.

Polymerization

[0367] In the process for preparing a branched polyolefin according tothe invention, an olefin is polymerized or copolymerized in the presenceof the above-mentioned olefin polymerization catalyst to obtain theaforesaid branched polyolefin. In FIG. 1, steps of a process forpreparing an olefin polymerization catalyst of the invention are shown.

[0368] In the polymerization, the components can be used in any way andin any order. Some examples of the polymerization processes are givenbelow.

[0369] (1) The component (A), the component (B) and the component (C)are fed to the polymerization reactor in an arbitrary order.

[0370] (2) A catalyst component wherein the component (A) is supportedon the carrier (D), the component (B) and the component (C) are fed tothe polymerization reactor in an arbitrary order.

[0371] (3) A catalyst component wherein the component (B) is supportedon the carrier (D), the component (A) and the component (C) are fed tothe polymerization reactor in an arbitrary order.

[0372] (4) A catalyst component wherein the component (C) is supportedon the carrier (D), the component (A) and the component (B) are fed tothe polymerization reactor in an arbitrary order.

[0373] (5) A catalyst component wherein the component (A) and thecomponent (B) are supported on the carrier (D), and the component (C)are fed to the polymerization reactor in an arbitrary order.

[0374] (6) A catalyst component wherein the component (A) is supportedon the carrier (D), a catalyst component wherein the component (B) issupported on the carrier (D), and the component (C) are fed to thepolymerization reactor in an arbitrary order.

[0375] (7) A catalyst component wherein the component (A) and thecomponent (C) are supported on the carrier (D), and the component (B)are fed to the polymerization reactor in an arbitrary order.

[0376] (8) A catalyst component wherein the component (B) and thecomponent (C) are supported on the carrier (D), and the component (A)are fed to the polymerization reactor in an arbitrary order.

[0377] (9) A catalyst component wherein the component (A), the component(B) and the component (C) are supported on the carrier (D) is fed to thepolymerization reactor.

[0378] In the above processes (1) to (8), two or more of the catalystcomponents may be previously contacted. In the processes (4), (7), (8)and (9) in which the component (C) is supported on the carrier (D), acomponent (C) which is not supported on the carrier (D) may beoptionally added in an arbitrary order. In this case, the components (C)may be the same or different.

[0379] An olefin may be prepolymerized onto the solid catalyst componentwherein the component (A) and the component (C) are supported on thecarrier (D), the solid catalyst component wherein the component (B) andthe component (C) are supported on the carrier (D) and the solidcatalyst component wherein the component (A), the component (B) and thecomponent (C) are supported on the carrier (D). On the prepolymerizedsolid catalyst component, a catalyst component may be further supported.

[0380] The polymerization can be carried out as any of liquid phasepolymerization, such as solution polymerization or suspensionpolymerization, and gas phase polymerization.

[0381] Examples of inert hydrocarbon media for use in the liquid phasepolymerization include aliphatic hydrocarbons, such as propane, butane,pentane, hexane, heptane, octane, decane, dodecane and kerosine;alicyclic hydrocarbons, such as cyclopentane, cyclohexane andmethylcyclopentane; aromatic hydrocarbons, such as benzene, toluene andxylene; halogenated hydrocarbons, such as ethylene chloride,chlorobenzene and dichloromethane; and mixtures of these hydrocarbons.The olefin itself can be used as the solvent.

[0382] When the polymerization of an olefin is carried out using theaforesaid olefin polymerization catalyst, the component (A) is used inan amount of usually 10⁻⁸ to 1 mol, preferably 10⁻⁷ to 0.5 mol, based on1 liter of the reaction volume, and the component (B) is used in anamount of usually 10⁻¹² to 10⁻² mol, preferably 10⁻¹⁰ to 10⁻³ mol, basedon 1 liter of the reaction volume. The component (A) and the component(B) are used in such amounts that the molar ratio (B/A) of the component(B) to the component (A) becomes usually 0.00001 to 100, preferably0.00005 to 10, more preferably 0.000075 to 1, still more preferably0.0001 to 0.5.

[0383] The component (C-1) is used in such an amount that the molarratio (C-1/M) of the component (C-1) to the whole transition metal atom(M) in the components (A) and (B) becomes usually 0.01 to 100000,preferably 0.05 to 50000.

[0384] The component (C-2) is used in such an amount that the molarratio (C-2/M) of the aluminum atom in the component (C-2) to thetransition metal atom (M) in the components (A) and (B) becomes usually10 to 500000, preferably 20 to 100000.

[0385] The component (C-3) is used in such an amount that the molarratio (C-3/M) of the component (C-3) to the transition metal atom (M) inthe components (A) and (B) becomes usually 1 to 10, preferably 1 to 5.

[0386] If the component (E) is used and if the component (C) is thecomponent (C-1), the component (E) is used in such an amount that themolar ratio (E/C-1) becomes usually 0.01 to 10, preferably 0.1 to 5. Ifthe component (E) is used and if the component (C) is the component(C-2), the component (E) is used in such an amount that the molar ratio(E/C-2) becomes usually 0.001 to 2, preferably 0.005 to 1. If thecomponent (E) is used and if the component (C) is the component (C-3),the component (E) is used in such an amount that the molar ratio (E/C-3)becomes usually 0.01 to 10, preferably 0.1 to 5.

[0387] The temperature for the polymerization of an olefin using theolefin polymerization catalyst is in the range of usually −50 to +200°C., preferably 0 to 170° C. The polymerization pressure is in the rangeof usually atmospheric pressure to 9.8 MPa (100 kg/cm²), preferablyatmospheric pressure to 4.9 MPa (50 kg/cm²). The polymerization reactioncan be carried out by any of batchwise, semi-continuous and continuousprocesses. The molecular weight of the resulting branched polyolefin canbe regulated by allowing hydrogen to be present in the polymerizationsystem or changing the polymerization temperature. The molecular weightcan be regulated also by changing the type of the component (C) used.

[0388] Examples of the olefins used in the polymerization include theaforesaid olefins of 2 to 20 carbon atoms. These olefins can be usedsingly or in combination of two or more kinds.

[0389] In the present invention, a branched polyolefin can be preparedby polymerizing an olefin in the presence of the olefin polymerizationcatalyst containing the transition metal compound (A) and the transitionmetal component (B) under one kind of react ion condition, or can beprepared by polymerizing an olefin in the presence of the olefinpolymerization catalyst under two kinds of reaction conditions.

[0390] It is thought that when the polymerization of an olefin iscarried out in the presence of the olefin polymerization catalystcontaining the transition metal compound (A) and the transition metalcompound (B), the vinyl-terminated macromer is produced by thetransition metal compound (B) and an olefin and the vinyl-terminatedmacromer are copolymerized by the transition metal compound (A) toprepare a branched polyolefin.

[0391] The transition metal compound (A) can produce a polymer of a highmolecular weight and can incorporate the vinyl-terminated macromer intothe growing polymer chain.

[0392] The transition metal compound (B) tends to produce a polymer of arelatively low molecular weight and does not incorporate thevinyl-terminated macromer into the growing polymer chain. The transitionmetal compound (B) can further produce polyethylene having extremely fewmethyl branches, and when olefins containing ethylene are polymerized,the transition metal compound (B) tends to selectively polymerizeethylene.

[0393] In the present invention, it is preferable to carry out thepreparation of the branched polyolefin continuously in two or morestages under different reaction conditions, and it is preferable tocarry out the polymerization continuously under at least two kinds ofreaction conditions in a polymerization reactor of one stage.

[0394] When the polymerization is carried out continuously under atleast two kinds of reaction conditions, the polymerization preferablyincludes polymerization conducted under such conditions that the yieldof a polymer produced by the transition metal compound (B) becomeshigher than the yield of a polymer produced by the transition metalcompound (A) (said polymerization sometimes being referred to as“polymerization B” hereinafter) and polymerization conducted under suchconditions that the yield of a polymer produced by the transition metalcompound (A) becomes higher than the yield of a polymer produced by thetransition metal compound (B) (said polymerization sometimes beingreferred to as “polymerization A” hereinafter). In this case, it ispreferable to conduct the polymerization B prior to the polymerizationA.

[0395] When the polymerization is carried out under the conditionsincluding the polymerization B and the polymerization A, a branchedpolyolefin can be prepared in a high yield, and when the polymerizationB is carried out prior to the polymerization A, a branched polyolefincan be prepared in a higher yield.

[0396] It is more preferable that, after the polymerization B iscompleted, the precipitated polymer is dissolved in the polymerizationsolvent or the system is maintained at a high temperature so as not toprecipitate a polymer dissolved in the polymerization solvent in thepolymerization process, and then the polymerization A is conducted.

[0397] When the polymerization is carried out as described above, thevinyl-terminated macromonomer is more homogeneously dispersed in thepolymerization solvent, and hence a branched polyolefin can be preparedin a higher yield.

[0398] Some examples of the processes for preparing a branchedpolyolefin including polymerization under such conditions that the yieldof a polymer produced by the transition metal compound (B) becomeshigher than the yield of a polymer produced by the transition metalcompound (A) and polymerization under such conditions that the yield ofa polymer produced by the transition metal compound (A) becomes higherthan the yield of a polymer produced by the transition metal compound(B) are given below.

[0399] (1) In the presence of the transition metal compound (A), thetransition metal compound (B) and the component (C), ethylene only ortwo or more kinds of olefins mainly containing ethylene are polymerized(former stage) and then propylene only or two or more kinds of olefinsmainly containing propylene are polymerized (latter stage). In thiscase, the molar ratio (B/A) of the transition metal compound (B) to thetransition metal compound (A) is so determined that the yield of apolymer produced by the transition metal compound (B) becomes higherthan the yield of a polymer produced by the transition metal compound(A) in the former stage and that the yield of a polymer produced by thetransition metal compound (A) becomes higher than the yield of a polymerproduced by the transition metal compound (B) in the latter stage. Morespecifically, the molar ratio (B/A) of the transition metal compound (B)to the transition metal compound (A) is determined in the range of 1/1to 1/1000, Preferably 1/10 to 1/500. The polymerization conditions ineach stage, such as polymerization temperature, polymerization pressureand amounts of the catalyst components used, are in the above ranges.

[0400] (2) In the presence of the transition metal compound (B) and thecomponent (C), ethylene only or two or more kinds of olefins mainlycontaining ethylene are polymerized (former stage), thereafter thetransition metal compound (A) is added, and then propylene only or twoor more kinds of olefins mainly containing propylene are polymerized(latter stage). In this case, the molar ratio (B/A) of the transitionmetal compound (B) to the transition metal compound (A) is so determinedthat the yield of a polymer produced by the transition metal compound(A) becomes higher than the yield of a polymer produced by thetransition metal compound (B) in the latter stage. More specifically,the molar ratio (B/A) of the transition metal compound (B) to thetransition metal compound (A) is determined in the range of 1/1 to1/1000, preferably 1/10 to 1/500. The polymerization conditions in eachstage, such as polymerization temperature, polymerization pressure andamounts of the catalyst components used, are in the above ranges.

[0401] (3) In the presence of the transition metal compound (B) and thecomponent (C), ethylene only or two or more kinds of olefins mainlycontaining ethylene are polymerized (former stage), thereafter a part ofthe resulting slurry is withdrawn and diluted with a polymerizationsolvent of the latter stage to give a solution, and to the solution isadded the transition metal compound (A). Then, ethylene only or two ormore kinds of olefins mainly containing ethylene are polymerized (latterstage). In this case, the molar ratio (B/A) of the transition metalcompound (B) to the transition metal compound (A) is so determined thatthe yield of a polymer produced by the transition metal compound (A)becomes higher than the yield of a polymer produced by the transitionmetal compound (B) in the latter stage. More specifically, the molarratio (B/A) of the transition metal compound (B) to the transition metalcompound (A) is determined in the range of 1/1 to 1/1000, preferably1/10 to 1/500. The polymerization conditions in each stage, such aspolymerization temperature, polymerization pressure and amounts of thecatalyst components used, are in the above ranges.

[0402] The yield of a polymer due to each transition metal compound ineach stage can be calculated by conducting each polymerization under thesame conditions as mentioned above except that only the transition metalcompound (A) or only the transition metal compound (B) is not contained.

[0403] By carrying out the polymerization of an olefin as describedabove, the branched polyolefin of the invention can be obtained, andwhether a vinyl-terminated macromonomer has been copolymerized in theresulting polymer or not can be judged by, for example, the followingmethods.

[0404] (1) Mw of a polymer obtained by the polymerization of an olefinin the presence of the vinyl-terminated macromonomer is higher than Mwof a polymer obtained by the polymerization of an olefin under the sameconditions except that the vinyl-terminated macromonomer is not present.

[0405] (2) The number of carbon atoms of branches having a length notshorter than that of hexyl as measured by ¹³C-NMR on a polymer obtainedby the polymerization of an olefin in the presence of thevinyl-terminated macromonomer is larger than the number of carbon atomsof branches having a length not shorter than that of hexyl as measuredby ¹³C-NMR on a polymer obtained by the polymerization of an olefinunder the same conditions except that the vinyl-terminated macromonomeris not present.

[0406] (3) The melting point (Tm) of a polymer obtained by thepolymerization of an olefin in the presence of the vinyl-terminatedmacromonomer is lower by not less than 1° C. than Tm of a polymerobtained by the polymerization of an olefin under the same conditionsexcept that the vinyl-terminated macromonomer is not present.

[0407] (4) The solubility of a polymer obtained by the polymerization ofan olefin in the presence of the vinyl-terminated macromonomer in aspecific solvent at a specific temperature is different from thesolubility of a mixture consisting of a polymer obtained by thepolymerization of an olefin under the same conditions except that thevinyl-terminated macromonomer is not present and a vinyl-terminatedmacromonomer in the same amount as that of the vinyl-terminatedmacromonomer present in the polymerization.

[0408] (5) The melt properties, such as melt viscosity and melt tension,of a polymer obtained by the polymerization of an olefin in the presenceof the vinyl-terminated macromonomer are different from those of apolymer obtained by the polymerization of an olefin under the sameconditions except that the vinyl-terminated macromonomer is not present.

[0409] Of the above methods, the methods (1) to (3) are preferably usedto make the judgment.

[0410] The number of carbon atoms of branches having a length notshorter than that of hexyl as measured by ¹³C-NMR, that is described inthe method (2), is calculated by, for example, the aforesaid method.

[0411] The melting point (Tm) described in the method (3) is measuredin, for example, the following manner.

[0412] Measurement of Melting Point (Tm)

[0413] An endothermic curve of a differential scanning calorimeter (DSC)is sought, and the temperature at the maximum peak position is taken asa melting point (Tm). In the measurement, a sample is placed in analuminum pan, heated up to 20° C. at a rate of 10° C./min, maintained at200° C. for 5 minutes, then cooled to −150° C. at a rate of 20° C./minand then heated at a rate of 10° C./min to obtain the second-runendothermic curve, and from the endothermic curve, the melting point isfound.

Effect of the Invention

[0414] The branched polyolefin according to the invention is excellentin moldability and mechanical strength.

[0415] The branched polyolefin according to the invention has largetemperature dependence of viscosity, so that in the vicinity of the diewhere the resin temperature is high, the viscosity is low, and hence thepolyolefin is easily stretched. On the other hand, at the place apartfrom the vicinity of the die, the resin temperature is lowered, andthereby the viscosity is abruptly increased, so that even if there issome temperature unevenness, such stretching as reflects the temperatureunevenness does not take place at the place apart from the die becausethe viscosity ratio between the place apart from the die and thevicinity of the die is large, and as a result, production of a film freefrom stretching nonuniformity is feasible. Moreover, the branchedpolyolefin has a low melt tension, and hence the branched polyolefin ishardly distortion-hardened even if stretched. Therefore, drawdown islikely to take place, and it becomes feasible to take off at a highspeed.

[0416] The process for preparing a branched polyolefin according to theinvention can efficiently prepare a branched polyolefin having theabove-mentioned properties.

EXAMPLE

[0417] The present invention is further described with reference to thefollowing examples, but it should be construed that the invention is inno way limited to those examples.

[0418] In the examples and the comparative examples, a compoundrepresented by the following formula (A-1) (transition metal compound(A-1)) and a compound represented by the following formula (B-1)(transition metal compound (B-1)) were used as the transition metalcompounds.

Example 1 Polymerization

[0419] In a 1-liter glass polymerization reactor thoroughly purged withnitrogen, 750 ml of purified toluene was placed, and ethylene was passedthrough the reactor for 20 minutes at a flow rate of 100 l/hr. Then, thesystem was heated to 50° C., and 40 mmol of commercially availablemethylaluminoxane (from Tohso Akuzo Co., referred to as “MAO-1”hereinafter) was added. Further, 0.3 mmol of the transition metalcompound (A-1) and 0.015 mmol of the transition metal compound (B-1)were added. With stirring, ethylene was passed through the reactor at50° C. for 10 minutes at a flow rate of 100 l/hr to performpolymerization. After the polymerization was conducted for a givenperiod of time, a small amount of isobutyl alcohol was added, and thewhole amount of the resulting slurry was introduced into a mixed liquidof 2 liters of methanol and 2 liters of acetone. After the mixture wasallowed to stand still for one night, a small amount of hydrochloricacid was added, followed by filtration. The polymer separated byfiltration was washed with 1 liter of methanol and then vacuum dried at80° C. for 10 hours. The yield of the polymer (1-a) thus obtained was21.2 g.

Preparation of Measuring Sample

[0420] To the resulting polymer, 0.1% by weight of Irganox 1076™(available from Ciba Specialty Chemicals, Co.) and 0.1% by weight ofIrgafos 168™ (available from Ciba Specialty Chemicals, Co.) were addedas heat stabilizers, and the mixture was melt kneaded by a Toyo SeikiSeisakusho laboplastomill at a resin temperature of 180° C. for 5minutes at a revolution number of 50 r.p.m. The polymer was then placedin a mold having a thickness of 2 mm and subjected to press moldingusing a Shindo Kinzoku Kogyosho press molding machine under theconditions of a preheating temperature of 190° C., a preheating time of5 minutes, a heating temperature of 190° C., a heating time of 2minutes, a heating pressure of 100 kg/cm², a cooling temperature of 20°C., a cooling time of 5 minutes and a cooling pressure of 100 kg/cm².Thus, a sample sheet having a thickness of 2 mm was prepared.

Analysis of Polymer (1-a)

[0421] When the polymer (1-a) was analyzed by GPC, two peaks weredetected. In FIG. 2, a peak-separated GPC chart is shown. With respectto one peak, Mw was 73,000, Mw/Mn was 2.8, and the peak intensity ratiowas 66.3%, while with respect to the other peak, Mw was 2,000, Mw/Mn was1.7, and the peak intensity ratio was 33.7%. MFR, MT and Ea of theresulting polymer are set forth in Table 1.

Judgment of Presence of Long-Chain Branch

[0422] With respect to one peak of the peaks of the polymer (1-a)detected by GPC, Mw was 73,000, as described above. It is thought that amacromonomer corresponding to the polymer (1-c) obtained in thelater-described Comparative Example 2 was copolymerized by thetransition metal compound (B-1), and hence the polymer (1-a) showed ahigher Mw value than the polymer (1-b) obtained in the later-describedComparative Example 1. That is to say, the polymer (1-a) could be judgedto be a branched polymer with a side chain having Mw of 2, 000 andscarcely any methyl branch (lower than the limit of detection). When theyield ratio between the polymer (1-b) and the polymer (1-c) was watched,the ratio of the low-molecular weight portion in the polymer (1-a) oughtto have been higher than that of the high-molecular weight portion, butthe GPC peak intensity ratio of the high-molecular weight portion in thepolymer (1-a) was higher than that of the low-molecular weight portion,and this suggests that the polymer (1-a) is a branched polymer.

Comparative Example 1

[0423] A polymer (1-b) was obtained in the same manner as in the“polymerization” of Example 1, except that the transition metal compound(B-1) was not added. The yield was 15.6 g, Mw was 56,000, Mw/Mn was 4.2,and only one peak was detected by GPC.

Comparative Example 2

[0424] A polymer (1-c) was obtained in the same manner as in the“polymerization” of Example 1, except that the transition metal compound(A-1) was not added. The yield was 42.4 g, Mw was 2,000, Mw/Mn was 2.1,and only one peak was detected by GPC. As a result of measurement ofmethyl branch of the polymer, no methyl branch was detected.

Comparative Example 3

[0425] MFR, MT and Ea of a commercially available ethylene/1-hexenecopolymer (trade name: Evolue SP2040, from Mitsui Chemicals, Inc. )obtained by gas phase polymerization are set forth in Table. 1.

[0426] This ethylene/1-hexene copolymer had MT and MFR satisfying arelation represented by MT≦2.2×MFR^(−0.88) but had Ea deviating from therange of Ea≧0.385×C+28.7. From this fact, this copolymer is presumed tohave a primary structure containing no long-chain branch.

Comparative Example 4

[0427] MFR, MT and Ea of a commercially available ethylene/1-octenecopolymer (tradename: Affinity PL1845, from The Dow Chemicals, Co.)obtained by solution polymerization are set forth in Table. 1.

[0428] This ethylene/1-octene copolymer had Ea satisfying the requisiteof Ea≧0.385×C+28.7 but had MT and MFR not satisfying a relationrepresented by MT≦2.2×MFR^(−0.88). From this fact, this copolymer ispresumed to have a primary structure having a long-chain branch of alength of about twice the molecular weight between the entanglementpoints. Comonomer Branch of hexyl content MFR Ea (or longer) groupComonomer (C) g/10 MT ×10³ number of Type % by weight min g *1 J/mol *2branches/1000C Ex. 1 — 0 1.6 0.60 1.45 45.0 30.0 1.4 Comp. Ex. 31-hexene 10 3.8 0.50 0.68 31.5 32.5 0 Comp. Ex. 4 1-octene 13 3.5 0.790.73 40.3 33.7 19.8

Example 2 Polymerization

[0429] In a 500-ml glass polymerization reactor thoroughly purged withnitrogen, 250 ml of purified toluene was placed, and ethylene was passedthrough the reactor for 20 minutes at a flow rate of 100 l/hr. Then, thesystem was heated to 50° C., followed by adding 1.25 mmol ofmethylaluminoxane (referred to as “MAO-2” hereinafter) as a toluenesolution having been obtained by vacuum distilling toluene from atoluene solution of Albemar methylaluminoxane at 40° C. and then addingdehydrated toluene again. Further, 0.005 mmol of the transition metalcompound (A-1) and 0.00025 mmol of the transition metal compound (B-1)were added. With stirring, ethylene was passed through the reactor at50° C. for 5 minutes at a flow rate of 100 l/hr to performpolymerization. After the polymerization was conducted for a givenperiod of time, a small amount of isobutyl alcohol was added, and thewhole amount of the resulting slurry was introduced into 1 liter ofmethanol. After the mixture was allowed to stand still for one night, asmall amount of hydrochloric acid was added, followed by filtration. Thepolymer separated by filtration was washed with 1 liter of methanol andthen vacuum dried at 80° C. for 10 hours. The yield of the polymer (2-a)thus obtained was 0.65 g.

Analysis of Polymer (2-a)

[0430] When the polymer (2-a) was analyzed by DSC, Tm was 130° C. Whenthe polymer was analyzed by GPC, two peaks were detected. With respectto one peak, Mw was 180,000, Mw/Mn was 2.4, and the peak intensity ratiowas 64%, while with respect to the other peak, Mw was 8,000, Mw/Mn was2.0, and the peak intensity ratio was 36%.

Judgment of Presence of Long-Chain Branch

[0431] With respect to one peak of the peaks of the polymer (2-a)detected by GPC, Mw was 180,000, as described above. It is thought thata macromonomer corresponding to the polymer (2-c) obtained in thelater-described Comparative Example 6 was polymerized by the transitionmetal compound (B-1), and hence the polymer (2-a) showed a higher Mwvalue than the polymer (2-b) obtained in the later-described ComparativeExample 5. That is to say, the polymer (2-a) could be judged to be abranched polymer with a side chain having Mw of 8,000 and scarcely anymethyl branch (lower than the limit of detection).

[0432] When the yields of the polymer (2 b) and the polymer (2-c) werewatched, the yield of the low-molecular weight portion in the polymer(2-a) which was a polymer produced by the transition metal compound(A-1) and the transition metal compound (B-1) ought to have been higherthan that of the high-molecular weight portion, but the GPC peakintensity ratio of the high-molecular weight portion in the polymer(2-a) was higher than that of the low-molecular weight portion, and thissuggests that the polymer (2-a) is not a mixture of a polymer producedby the transition metal compound (A-1) and a polymer produced by thetransition metal compound (B-1) but a branched polymer wherein a part ofthe polymer (vinyl-terminated macromer) produced by the transition metalcompound (B-1) was copolymerized by the transition metal compound (A-1).

Comparative Example 5

[0433] A polymer (2-b) was obtained in the same manner as in the“polymerization” of Example 2, except that the transition metal compound(B-1) was not added. The yield was 0.18 g, Tm was 133° C., Mw was110,000, Mw/Mn was 4.1, and only one peak was detected by GPC.

Comparative Example 6

[0434] A polymer (2-c) was obtained in the same manner as in the“polymerization” of Example 2, except that the transition metal compound(A-1) was not added. The yield was 0.96 g, Tm was 128° C., Mw was 8,000,Mw/Mn was 2.1, and only one peak was detected by GPC. As a result ofmeasurement of methyl branch of the polymer, no methyl branch wasdetected.

Example 3 Polymerization

[0435] In a 500-ml glass polymerization reactor thoroughly purged withnitrogen, 250 ml of purified toluene was placed, and ethylene was passedthrough the reactor for 20 minutes at a flow rate of 100 l/hr. Then, thesystem was heated to 50° C., and 1.25 mmol of MAO-1 was added. Further,0.005 mmol of the transition metal compound (A-1) and 0.00025 mmol ofthe transition metal compound (B-1) were added. With stirring, ethylenewas passed through the reactor at 50° C. for 5 minutes at a flow rate of100 l/hr to perform polymerization.

[0436] Then, feeding of ethylene was stopped, and with stirring,propylene was passed through the reactor at 50° C. for 1 hour at a flowrate of 100 l/hr to perform polymerization of the second stage. Afterthe polymerization was conducted for a given period of time, a smallamount of isobutyl alcohol was added, and the whole amount of theresulting slurry was introduced into 1 liter of methanol. After themixture was allowed to stand still for one night, a small amount ofhydrochloric acid was added, followed by filtration. The polymerseparated by filtration was washed with 1 liter of methanol and thenvacuum dried at 80° C. for 10 hours. The yield of the polymer (3-a) thusobtained was 8.39 g.

Analysis of Polymer (3-a)

[0437] When the polymer (3-a) was analyzed by DSC, Tm was 125° C. Whenthe polymer was analyzed by GPC, a single peak having a shoulder peakwith Mw of about 8,000 was detected. With respect to this peak, Mw was210,000, and Mw/Mn was 2.6.

Judgment of Presence of Long-Chain Branch

[0438] The Mw of the polymer (3-a) was 180,000, as described above, andthis Mw was higher by 140,000 than the Mw of the polymer (3-b) obtainedin the later-described Comparative Example 7. It is thought that avinyl-terminated macromonomer corresponding to the polymer (3-c)obtained in the later-described Comparative Example 8 was copolymerizedby the transition metal compound (B-1), and hence the polymer (3-a)showed a higher Mw value than the polymer (3-b). That is to say, thepolymer (3-a) could be judged to be a branched polymer with a side chainhaving Mw of 8,000 and scarcely any methyl branch (lower than the Limitof detection). The polymer (3-a) showed Tm lower than that of thepolymer (3-b) and that of the polymer (3-c), and this also suggests thatthe polymer (3-a) is a branched polymer.

Comparative Example 7

[0439] A polymer (3-b) was obtained in the same manner as in the“polymerization” of Example 3, except that the transition metal compound(B-1) was not added. The yield was 4.5 g, Tm was 129° C., Mw was140,000, Mw/Mn was 2.3, and a single peak was detected by GPC.

Comparative Example 8

[0440] A polymer (3-c) was obtained in the same manner as in the“polymerization” of Example 3, except that the transition metal compound(A-1) was not added. The yield was 1.0 g, Tm was 128° C., Mw was 8,000,Mw/Mn was 2.2, and a single peak was detected by GPC. As a result ofmeasurement of methyl branch of the polymer, no methyl branch wasdetected.

What is claimed is:
 1. A polymer having a melt tension (MT (g)) that issubstantially the same as or lower than that of a conventional polymerwhich is substantially the same as the polymer in the recurring unit ofthe main skeleton, the molecular weight, the molecular weightdistribution and the crystallinity, and having a flow activation energy(Ea (KJ/mol)) that is larger than a value obtained by adding 5 KJ/mol tothe Ea value of the conventional polymer.
 2. The polymer as claimed inclaim 1, wherein the recurring unit of the main skeleton is constitutedof carbon and hydrogen, and optionally oxygen, and the polymer issubstantially thermoplastic.
 3. The polymer as claimed in claim 2,wherein the main skeleton is constituted of olefins of 2 to 8 carbonatoms.
 4. A branched polyolefin comprising 50 to 100% by mol ofrecurring units derived from ethylene and 0 to 50% by mol of recurringunits derived from an α-olefin of 3 to 7 carbon atoms and having thefollowing properties: the flow activation energy (Ea (KJ/mol)) and theα-olefin content (C (% by weight)) satisfy the following relation: inthe case where the number of carbon atoms of the α-olefin is 3 and C≧10%by weight: Ea≧0.130×C+28.7, in the case where the number of carbon atomsof the α-olefin is 4 to 7 and C≧4.1% by weight: Ea≧0.385×C+28.7, in thecase where the number of carbon atoms of the α-olefin is 3 and C<10% byweight (including the case where the α-olefin content is 0), and in thecase where the number of carbon atoms of the α-olefin is 4 to 7 andC<4.1% by weight: Ea≧30, and the melt tension (MT (g)) and the melt flowrate (MFR (g/10 min)) satisfy the following relation:MT≦2.2×MFR^(−0.88).
 5. The branched polyolefin as claimed in claim 4,comprising: (i) recurring units derived from at least one olefinselected from ethylene and olefins of 3 to 7 carbon atoms, and (ii)recurring units derived from a vinyl-terminated macromonomer comprising50 to 100% by mol of recurring units derived from ethylene and 50 to 0%by mol of recurring units derived from an olefin of 4 to 7 carbon atoms,having a weight-average molecular weight of 600 to 3,500 and having lessthan 0.1 methyl branch, as measured by ¹³C-NMR, based on 1,000 carbonatoms.
 6. A branched polyolefin comprising 50 to 100% by mol ofrecurring units derived from ethylene and 0 to 50% by mol of recurringunits derived from an α-olefin of 8 to 20 carbon atoms and having thefollowing properties: the flow activation energy (Ea (KJ/mol)) and theα-olefin content (C (% by weight)) satisfy the following relation: inthe case of C≧4.1% by weight: Ea≧0.385×C+28.7, in the case of C<4.1% byweight: Ea≧30, and the melt tension (MT (g)) and the melt flow rate (MFR(g/10 min)) satisfy the following relation: MT≦2.2×MFR^(−0.88).
 7. Thebranched polyolefin as claimed in claim 6, comprising: (i) recurringunits derived from at least one olefin selected from ethylene andolefins of 8 to 20 carbon atoms, and (ii) recurring units derived from avinyl-terminated macromonomer comprising 50 to 100% by mol of recurringunits derived from ethylene and 50 to 0% by mol of recurring unitsderived from an olefin of 3 to 20 carbon atoms, having a weight-averagemolecular weight of 600 to 3,500 and having less than 0.1 methyl branch,as measured by ¹³C-NMR, based on 1,000 carbon atoms.
 8. A branchedpolyolefin comprising: (i) recurring units derived from at least oneolefin selected from olefins of 2 to 20 carbon atoms, and (ii) recurringunits derived from a vinyl-terminated macromonomer comprising 50 to 100%by mol of recurring units derived from ethylene and 50 to 0% by mol ofrecurring units derived from an olefin of 4 to 20 carbon atoms, having aweight-average molecular weight of 600 to 200,000 and having less than0.1 methyl branch, as measured by ¹³C-NMR, based on 1,000 carbon atoms.9. The branched polyolefin as claimed in claim 8, wherein theweight-average molecular weight is in the range of 600 to 3,500.
 10. Aprocess for preparing a branched polyolefin, comprising polymerizing atleast one olefin selected from olefins of 2 to 20 carbon atoms using anolefin polymerization catalyst comprising: (A) a transition metalcompound containing a ligand having cyclopentadienyl skeleton, (B) atransition metal compound represented by the following formula (I), and(C) at least one compound selected from: (C-1) an organometalliccompound, (C-2) an organoaluminum oxy-compound, and (C-3) a compoundwhich reacts with the transition metal compound (A) or the transitionmetal compound (B) to form an ion pair, to prepare the branchedpolyolefin of any one of claims 4, 6 and 8;

wherein M is a transition metal atom of Group 4 to Group 5 of theperiodic table, m is an integer of 1 to 2, R¹ is an aliphatichydrocarbon group or an alicyclic hydrocarbon group, R² to R⁵ may be thesame or different and are each a hydrogen atom, a hydrocarbon group, ahydrocarbon-substituted silyl group, an oxygen-containing group, anitrogen-containing group or a sulfur containing group, R⁶ is ahydrocarbon group or a hydrocarbon-substituted silyl group, n is anumber satisfying a valence of M, X is a hydrogen atom, a halogen atom,a hydrocarbon group, an oxygen containing group, a sulfur-containinggroup, a nitrogen-containing group, a boron-containing group, analuminum-containing group, a phosphorus-containing group, ahalogen-containing group, a heterocyclic compound residue, asilicon-containing group, a germanium-containing group or atin-containing group, and when n is 2 or greater, plural groupsindicated by X may be the same or different, and plural groups indicatedby X may be bonded to form a ring.
 11. The process for preparing abranched polyolefin as claimed in claim 10, wherein the polymerizationis carried out continuously under at least two different polymerizationconditions, and the polymerization includes polymerization conductedunder such condition that the yield of a polymer produced by thetransition metal compound (B) becomes higher than the yield of a polymerproduced by the transition metal compound (A) and polymerizationconducted under such conditions that the yield of a polymer produced bythe transition metal compound (A) becomes higher than the yield of apolymer produced by the transition metal compound (B).